.\" Copyright (c) 2013 by Turbo Fredriksson <turbo@bayour.com>. All rights reserved.
.\" Copyright (c) 2019, 2021 by Delphix. All rights reserved.
.\" Copyright (c) 2019 Datto Inc.
+.\" Copyright (c) 2023, 2024 Klara, Inc.
.\" The contents of this file are subject to the terms of the Common Development
.\" and Distribution License (the "License"). You may not use this file except
.\" in compliance with the License. You can obtain a copy of the license at
.\" own identifying information:
.\" Portions Copyright [yyyy] [name of copyright owner]
.\"
-.Dd June 1, 2021
+.Dd January 9, 2024
.Dt ZFS 4
.Os
.
.Sh DESCRIPTION
The ZFS module supports these parameters:
.Bl -tag -width Ds
-.It Sy dbuf_cache_max_bytes Ns = Ns Sy ULONG_MAX Ns B Pq ulong
+.It Sy dbuf_cache_max_bytes Ns = Ns Sy UINT64_MAX Ns B Pq u64
Maximum size in bytes of the dbuf cache.
The target size is determined by the MIN versus
.No 1/2^ Ns Sy dbuf_cache_shift Pq 1/32nd
.Pa /proc/spl/kstat/zfs/dbufstats
kstat.
.
-.It Sy dbuf_metadata_cache_max_bytes Ns = Ns Sy ULONG_MAX Ns B Pq ulong
+.It Sy dbuf_metadata_cache_max_bytes Ns = Ns Sy UINT64_MAX Ns B Pq u64
Maximum size in bytes of the metadata dbuf cache.
The target size is determined by the MIN versus
.No 1/2^ Ns Sy dbuf_metadata_cache_shift Pq 1/64th
.Sy dbuf_cache_max_bytes
when the evict thread stops evicting dbufs.
.
-.It Sy dbuf_cache_shift Ns = Ns Sy 5 Pq int
+.It Sy dbuf_cache_shift Ns = Ns Sy 5 Pq uint
Set the size of the dbuf cache
.Pq Sy dbuf_cache_max_bytes
to a log2 fraction of the target ARC size.
.
-.It Sy dbuf_metadata_cache_shift Ns = Ns Sy 6 Pq int
+.It Sy dbuf_metadata_cache_shift Ns = Ns Sy 6 Pq uint
Set the size of the dbuf metadata cache
.Pq Sy dbuf_metadata_cache_max_bytes
to a log2 fraction of the target ARC size.
.Sy 0
the array is dynamically sized based on total system memory.
.
-.It Sy dmu_object_alloc_chunk_shift Ns = Ns Sy 7 Po 128 Pc Pq int
+.It Sy dmu_object_alloc_chunk_shift Ns = Ns Sy 7 Po 128 Pc Pq uint
dnode slots allocated in a single operation as a power of 2.
The default value minimizes lock contention for the bulk operation performed.
.
-.It Sy dmu_prefetch_max Ns = Ns Sy 134217728 Ns B Po 128 MiB Pc Pq int
+.It Sy dmu_prefetch_max Ns = Ns Sy 134217728 Ns B Po 128 MiB Pc Pq uint
Limit the amount we can prefetch with one call to this amount in bytes.
This helps to limit the amount of memory that can be used by prefetching.
.
Turbo L2ARC warm-up.
When the L2ARC is cold the fill interval will be set as fast as possible.
.
-.It Sy l2arc_feed_min_ms Ns = Ns Sy 200 Pq ulong
+.It Sy l2arc_feed_min_ms Ns = Ns Sy 200 Pq u64
Min feed interval in milliseconds.
Requires
.Sy l2arc_feed_again Ns = Ns Ar 1
and only applicable in related situations.
.
-.It Sy l2arc_feed_secs Ns = Ns Sy 1 Pq ulong
+.It Sy l2arc_feed_secs Ns = Ns Sy 1 Pq u64
Seconds between L2ARC writing.
.
-.It Sy l2arc_headroom Ns = Ns Sy 2 Pq ulong
+.It Sy l2arc_headroom Ns = Ns Sy 8 Pq u64
How far through the ARC lists to search for L2ARC cacheable content,
expressed as a multiplier of
.Sy l2arc_write_max .
.Sy 0 ,
allowing the full length of ARC lists to be searched for cacheable content.
.
-.It Sy l2arc_headroom_boost Ns = Ns Sy 200 Ns % Pq ulong
+.It Sy l2arc_headroom_boost Ns = Ns Sy 200 Ns % Pq u64
Scales
.Sy l2arc_headroom
by this percentage when L2ARC contents are being successfully compressed
arcstats can be used to decide if toggling this option is appropriate
for the current workload.
.
-.It Sy l2arc_meta_percent Ns = Ns Sy 33 Ns % Pq int
+.It Sy l2arc_meta_percent Ns = Ns Sy 33 Ns % Pq uint
Percent of ARC size allowed for L2ARC-only headers.
Since L2ARC buffers are not evicted on memory pressure,
too many headers on a system with an irrationally large L2ARC
can render it slow or unusable.
This parameter limits L2ARC writes and rebuilds to achieve the target.
.
-.It Sy l2arc_trim_ahead Ns = Ns Sy 0 Ns % Pq ulong
+.It Sy l2arc_trim_ahead Ns = Ns Sy 0 Ns % Pq u64
Trims ahead of the current write size
.Pq Sy l2arc_write_max
on L2ARC devices by this percentage of write size if we have filled the device.
.It Sy l2arc_norw Ns = Ns Sy 0 Ns | Ns 1 Pq int
No reads during writes.
.
-.It Sy l2arc_write_boost Ns = Ns Sy 8388608 Ns B Po 8 MiB Pc Pq ulong
+.It Sy l2arc_write_boost Ns = Ns Sy 33554432 Ns B Po 32 MiB Pc Pq u64
Cold L2ARC devices will have
.Sy l2arc_write_max
increased by this amount while they remain cold.
.
-.It Sy l2arc_write_max Ns = Ns Sy 8388608 Ns B Po 8 MiB Pc Pq ulong
+.It Sy l2arc_write_max Ns = Ns Sy 33554432 Ns B Po 32 MiB Pc Pq u64
Max write bytes per interval.
.
.It Sy l2arc_rebuild_enabled Ns = Ns Sy 1 Ns | Ns 0 Pq int
in reading stored log metadata, or the metadata
has become somehow fragmented/unusable).
.
-.It Sy l2arc_rebuild_blocks_min_l2size Ns = Ns Sy 1073741824 Ns B Po 1 GiB Pc Pq ulong
+.It Sy l2arc_rebuild_blocks_min_l2size Ns = Ns Sy 1073741824 Ns B Po 1 GiB Pc Pq u64
Mininum size of an L2ARC device required in order to write log blocks in it.
The log blocks are used upon importing the pool to rebuild the persistent L2ARC.
.Pp
evicts is significant compared to the amount of restored L2ARC data.
In this case, do not write log blocks in L2ARC in order not to waste space.
.
-.It Sy metaslab_aliquot Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq ulong
+.It Sy metaslab_aliquot Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq u64
Metaslab granularity, in bytes.
This is roughly similar to what would be referred to as the "stripe size"
in traditional RAID arrays.
Enable metaslab group biasing based on their vdevs' over- or under-utilization
relative to the pool.
.
-.It Sy metaslab_force_ganging Ns = Ns Sy 16777217 Ns B Po 16 MiB + 1 B Pc Pq ulong
+.It Sy metaslab_force_ganging Ns = Ns Sy 16777217 Ns B Po 16 MiB + 1 B Pc Pq u64
Make some blocks above a certain size be gang blocks.
This option is used by the test suite to facilitate testing.
.
-.It Sy zfs_history_output_max Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq int
+.It Sy metaslab_force_ganging_pct Ns = Ns Sy 3 Ns % Pq uint
+For blocks that could be forced to be a gang block (due to
+.Sy metaslab_force_ganging ) ,
+force this many of them to be gang blocks.
+.
+.It Sy brt_zap_prefetch Ns = Ns Sy 1 Ns | Ns 0 Pq int
+Controls prefetching BRT records for blocks which are going to be cloned.
+.
+.It Sy brt_zap_default_bs Ns = Ns Sy 12 Po 4 KiB Pc Pq int
+Default BRT ZAP data block size as a power of 2. Note that changing this after
+creating a BRT on the pool will not affect existing BRTs, only newly created
+ones.
+.
+.It Sy brt_zap_default_ibs Ns = Ns Sy 12 Po 4 KiB Pc Pq int
+Default BRT ZAP indirect block size as a power of 2. Note that changing this
+after creating a BRT on the pool will not affect existing BRTs, only newly
+created ones.
+.
+.It Sy ddt_zap_default_bs Ns = Ns Sy 15 Po 32 KiB Pc Pq int
+Default DDT ZAP data block size as a power of 2. Note that changing this after
+creating a DDT on the pool will not affect existing DDTs, only newly created
+ones.
+.
+.It Sy ddt_zap_default_ibs Ns = Ns Sy 15 Po 32 KiB Pc Pq int
+Default DDT ZAP indirect block size as a power of 2. Note that changing this
+after creating a DDT on the pool will not affect existing DDTs, only newly
+created ones.
+.
+.It Sy zfs_default_bs Ns = Ns Sy 9 Po 512 B Pc Pq int
+Default dnode block size as a power of 2.
+.
+.It Sy zfs_default_ibs Ns = Ns Sy 17 Po 128 KiB Pc Pq int
+Default dnode indirect block size as a power of 2.
+.
+.It Sy zfs_history_output_max Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq u64
When attempting to log an output nvlist of an ioctl in the on-disk history,
the output will not be stored if it is larger than this size (in bytes).
This must be less than
.It Sy metaslab_fragmentation_factor_enabled Ns = Ns Sy 1 Ns | Ns 0 Pq int
Enable use of the fragmentation metric in computing metaslab weights.
.
-.It Sy metaslab_df_max_search Ns = Ns Sy 16777216 Ns B Po 16 MiB Pc Pq int
+.It Sy metaslab_df_max_search Ns = Ns Sy 16777216 Ns B Po 16 MiB Pc Pq uint
Maximum distance to search forward from the last offset.
Without this limit, fragmented pools can see
.Em >100`000
If set, we will use the largest free segment.
If unset, we will use a segment of at least the requested size.
.
-.It Sy zfs_metaslab_max_size_cache_sec Ns = Ns Sy 3600 Ns s Po 1 hour Pc Pq ulong
+.It Sy zfs_metaslab_max_size_cache_sec Ns = Ns Sy 3600 Ns s Po 1 hour Pc Pq u64
When we unload a metaslab, we cache the size of the largest free chunk.
We use that cached size to determine whether or not to load a metaslab
for a given allocation.
we stop considering the cached max size and start
considering only the histogram instead.
.
-.It Sy zfs_metaslab_mem_limit Ns = Ns Sy 25 Ns % Pq int
+.It Sy zfs_metaslab_mem_limit Ns = Ns Sy 25 Ns % Pq uint
When we are loading a new metaslab, we check the amount of memory being used
to store metaslab range trees.
If it is over a threshold, we attempt to unload the least recently used metaslab
If that fails then we will have a multi-layer gang block.
.El
.
-.It Sy zfs_metaslab_find_max_tries Ns = Ns Sy 100 Pq int
+.It Sy zfs_metaslab_find_max_tries Ns = Ns Sy 100 Pq uint
When not trying hard, we only consider this number of the best metaslabs.
This improves performance, especially when there are many metaslabs per vdev
and the allocation can't actually be satisfied
(so we would otherwise iterate all metaslabs).
.
-.It Sy zfs_vdev_default_ms_count Ns = Ns Sy 200 Pq int
+.It Sy zfs_vdev_default_ms_count Ns = Ns Sy 200 Pq uint
When a vdev is added, target this number of metaslabs per top-level vdev.
.
-.It Sy zfs_vdev_default_ms_shift Ns = Ns Sy 29 Po 512 MiB Pc Pq int
-Default limit for metaslab size.
+.It Sy zfs_vdev_default_ms_shift Ns = Ns Sy 29 Po 512 MiB Pc Pq uint
+Default lower limit for metaslab size.
+.
+.It Sy zfs_vdev_max_ms_shift Ns = Ns Sy 34 Po 16 GiB Pc Pq uint
+Default upper limit for metaslab size.
.
-.It Sy zfs_vdev_max_auto_ashift Ns = Ns Sy 14 Pq ulong
-Maximum ashift used when optimizing for logical \[->] physical sector size on new
+.It Sy zfs_vdev_max_auto_ashift Ns = Ns Sy 14 Pq uint
+Maximum ashift used when optimizing for logical \[->] physical sector size on
+new
top-level vdevs.
May be increased up to
.Sy ASHIFT_MAX Po 16 Pc ,
but this may negatively impact pool space efficiency.
.
-.It Sy zfs_vdev_min_auto_ashift Ns = Ns Sy ASHIFT_MIN Po 9 Pc Pq ulong
+.It Sy zfs_vdev_min_auto_ashift Ns = Ns Sy ASHIFT_MIN Po 9 Pc Pq uint
Minimum ashift used when creating new top-level vdevs.
.
-.It Sy zfs_vdev_min_ms_count Ns = Ns Sy 16 Pq int
+.It Sy zfs_vdev_min_ms_count Ns = Ns Sy 16 Pq uint
Minimum number of metaslabs to create in a top-level vdev.
.
.It Sy vdev_validate_skip Ns = Ns Sy 0 Ns | Ns 1 Pq int
Changing is not recommended unless you know what you're doing
and are recovering a damaged label.
.
-.It Sy zfs_vdev_ms_count_limit Ns = Ns Sy 131072 Po 128k Pc Pq int
+.It Sy zfs_vdev_ms_count_limit Ns = Ns Sy 131072 Po 128k Pc Pq uint
Practical upper limit of total metaslabs per top-level vdev.
.
.It Sy metaslab_preload_enabled Ns = Ns Sy 1 Ns | Ns 0 Pq int
Enable metaslab group preloading.
.
+.It Sy metaslab_preload_limit Ns = Ns Sy 10 Pq uint
+Maximum number of metaslabs per group to preload
+.
+.It Sy metaslab_preload_pct Ns = Ns Sy 50 Pq uint
+Percentage of CPUs to run a metaslab preload taskq
+.
.It Sy metaslab_lba_weighting_enabled Ns = Ns Sy 1 Ns | Ns 0 Pq int
Give more weight to metaslabs with lower LBAs,
assuming they have greater bandwidth,
as is typically the case on a modern constant angular velocity disk drive.
.
-.It Sy metaslab_unload_delay Ns = Ns Sy 32 Pq int
+.It Sy metaslab_unload_delay Ns = Ns Sy 32 Pq uint
After a metaslab is used, we keep it loaded for this many TXGs, to attempt to
reduce unnecessary reloading.
Note that both this many TXGs and
.Sy metaslab_unload_delay_ms
milliseconds must pass before unloading will occur.
.
-.It Sy metaslab_unload_delay_ms Ns = Ns Sy 600000 Ns ms Po 10 min Pc Pq int
+.It Sy metaslab_unload_delay_ms Ns = Ns Sy 600000 Ns ms Po 10 min Pc Pq uint
After a metaslab is used, we keep it loaded for this many milliseconds,
to attempt to reduce unnecessary reloading.
Note, that both this many milliseconds and
.Sy metaslab_unload_delay
TXGs must pass before unloading will occur.
.
+.It Sy reference_history Ns = Ns Sy 3 Pq uint
+Maximum reference holders being tracked when reference_tracking_enable is
+active.
+.It Sy raidz_expand_max_copy_bytes Ns = Ns Sy 160MB Pq ulong
+Max amount of memory to use for RAID-Z expansion I/O.
+This limits how much I/O can be outstanding at once.
+.
+.It Sy raidz_expand_max_reflow_bytes Ns = Ns Sy 0 Pq ulong
+For testing, pause RAID-Z expansion when reflow amount reaches this value.
+.
+.It Sy raidz_io_aggregate_rows Ns = Ns Sy 4 Pq ulong
+For expanded RAID-Z, aggregate reads that have more rows than this.
+.
.It Sy reference_history Ns = Ns Sy 3 Pq int
-Maximum reference holders being tracked when reference_tracking_enable is active.
+Maximum reference holders being tracked when reference_tracking_enable is
+active.
.
.It Sy reference_tracking_enable Ns = Ns Sy 0 Ns | Ns 1 Pq int
Track reference holders to
.It Sy spa_config_path Ns = Ns Pa /etc/zfs/zpool.cache Pq charp
SPA config file.
.
-.It Sy spa_asize_inflation Ns = Ns Sy 24 Pq int
+.It Sy spa_asize_inflation Ns = Ns Sy 24 Pq uint
Multiplication factor used to estimate actual disk consumption from the
size of data being written.
The default value is a worst case estimate,
particularly if they operate close to quota or capacity limits.
.
.It Sy spa_load_print_vdev_tree Ns = Ns Sy 0 Ns | Ns 1 Pq int
-Whether to print the vdev tree in the debugging message buffer during pool import.
+Whether to print the vdev tree in the debugging message buffer during pool
+import.
.
.It Sy spa_load_verify_data Ns = Ns Sy 1 Ns | Ns 0 Pq int
Whether to traverse data blocks during an "extreme rewind"
If this parameter is unset, the traversal is not performed.
It can be toggled once the import has started to stop or start the traversal.
.
-.It Sy spa_load_verify_shift Ns = Ns Sy 4 Po 1/16th Pc Pq int
+.It Sy spa_load_verify_shift Ns = Ns Sy 4 Po 1/16th Pc Pq uint
Sets the maximum number of bytes to consume during pool import to the log2
fraction of the target ARC size.
.
most ZPL operations (e.g. write, create) will return
.Sy ENOSPC .
.
+.It Sy spa_num_allocators Ns = Ns Sy 4 Pq int
+Determines the number of block alloctators to use per spa instance.
+Capped by the number of actual CPUs in the system.
+.Pp
+Note that setting this value too high could result in performance
+degredation and/or excess fragmentation.
+.
.It Sy spa_upgrade_errlog_limit Ns = Ns Sy 0 Pq uint
Limits the number of on-disk error log entries that will be converted to the
new format when enabling the
feature.
The default is to convert all log entries.
.
-.It Sy vdev_removal_max_span Ns = Ns Sy 32768 Ns B Po 32 KiB Pc Pq int
+.It Sy vdev_removal_max_span Ns = Ns Sy 32768 Ns B Po 32 KiB Pc Pq uint
During top-level vdev removal, chunks of data are copied from the vdev
which may include free space in order to trade bandwidth for IOPS.
This parameter determines the maximum span of free space, in bytes,
which is a similar concept when doing
regular reads (but there's no reason it has to be the same).
.
-.It Sy vdev_file_logical_ashift Ns = Ns Sy 9 Po 512 B Pc Pq ulong
+.It Sy vdev_file_logical_ashift Ns = Ns Sy 9 Po 512 B Pc Pq u64
Logical ashift for file-based devices.
.
-.It Sy vdev_file_physical_ashift Ns = Ns Sy 9 Po 512 B Pc Pq ulong
+.It Sy vdev_file_physical_ashift Ns = Ns Sy 9 Po 512 B Pc Pq u64
Physical ashift for file-based devices.
.
.It Sy zap_iterate_prefetch Ns = Ns Sy 1 Ns | Ns 0 Pq int
However, this is limited by
.Sy dmu_prefetch_max .
.
-.It Sy zfetch_array_rd_sz Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq ulong
-If prefetching is enabled, disable prefetching for reads larger than this size.
+.It Sy zap_micro_max_size Ns = Ns Sy 131072 Ns B Po 128 KiB Pc Pq int
+Maximum micro ZAP size.
+A micro ZAP is upgraded to a fat ZAP, once it grows beyond the specified size.
+.
+.It Sy zfetch_hole_shift Ns = Ns Sy 2 Pq uint
+Log2 fraction of holes in speculative prefetch stream allowed for it to
+proceed.
.
.It Sy zfetch_min_distance Ns = Ns Sy 4194304 Ns B Po 4 MiB Pc Pq uint
Min bytes to prefetch per stream.
.It Sy zfetch_max_idistance Ns = Ns Sy 67108864 Ns B Po 64 MiB Pc Pq uint
Max bytes to prefetch indirects for per stream.
.
+.It Sy zfetch_max_reorder Ns = Ns Sy 16777216 Ns B Po 16 MiB Pc Pq uint
+Requests within this byte distance from the current prefetch stream position
+are considered parts of the stream, reordered due to parallel processing.
+Such requests do not advance the stream position immediately unless
+.Sy zfetch_hole_shift
+fill threshold is reached, but saved to fill holes in the stream later.
+.
.It Sy zfetch_max_streams Ns = Ns Sy 8 Pq uint
Max number of streams per zfetch (prefetch streams per file).
.
This is the minimum allocation size that will use scatter (page-based) ABDs.
Smaller allocations will use linear ABDs.
.
-.It Sy zfs_arc_dnode_limit Ns = Ns Sy 0 Ns B Pq ulong
+.It Sy zfs_arc_dnode_limit Ns = Ns Sy 0 Ns B Pq u64
When the number of bytes consumed by dnodes in the ARC exceeds this number of
bytes, try to unpin some of it in response to demand for non-metadata.
This value acts as a ceiling to the amount of dnode metadata, and defaults to
which indicates that a percent which is based on
.Sy zfs_arc_dnode_limit_percent
of the ARC meta buffers that may be used for dnodes.
-.Pp
-Also see
-.Sy zfs_arc_meta_prune
-which serves a similar purpose but is used
-when the amount of metadata in the ARC exceeds
-.Sy zfs_arc_meta_limit
-rather than in response to overall demand for non-metadata.
-.
-.It Sy zfs_arc_dnode_limit_percent Ns = Ns Sy 10 Ns % Pq ulong
+.It Sy zfs_arc_dnode_limit_percent Ns = Ns Sy 10 Ns % Pq u64
Percentage that can be consumed by dnodes of ARC meta buffers.
.Pp
See also
.Sy zfs_arc_dnode_limit ,
which serves a similar purpose but has a higher priority if nonzero.
.
-.It Sy zfs_arc_dnode_reduce_percent Ns = Ns Sy 10 Ns % Pq ulong
+.It Sy zfs_arc_dnode_reduce_percent Ns = Ns Sy 10 Ns % Pq u64
Percentage of ARC dnodes to try to scan in response to demand for non-metadata
when the number of bytes consumed by dnodes exceeds
.Sy zfs_arc_dnode_limit .
.
-.It Sy zfs_arc_average_blocksize Ns = Ns Sy 8192 Ns B Po 8 KiB Pc Pq int
+.It Sy zfs_arc_average_blocksize Ns = Ns Sy 8192 Ns B Po 8 KiB Pc Pq uint
The ARC's buffer hash table is sized based on the assumption of an average
block size of this value.
This works out to roughly 1 MiB of hash table per 1 GiB of physical memory
For configurations with a known larger average block size,
this value can be increased to reduce the memory footprint.
.
-.It Sy zfs_arc_eviction_pct Ns = Ns Sy 200 Ns % Pq int
+.It Sy zfs_arc_eviction_pct Ns = Ns Sy 200 Ns % Pq uint
When
.Fn arc_is_overflowing ,
.Fn arc_get_data_impl
even during the potentially long time that
.Sy arc_size No is more than Sy arc_c .
.
-.It Sy zfs_arc_evict_batch_limit Ns = Ns Sy 10 Pq int
+.It Sy zfs_arc_evict_batch_limit Ns = Ns Sy 10 Pq uint
Number ARC headers to evict per sub-list before proceeding to another sub-list.
This batch-style operation prevents entire sub-lists from being evicted at once
but comes at a cost of additional unlocking and locking.
.
-.It Sy zfs_arc_grow_retry Ns = Ns Sy 0 Ns s Pq int
+.It Sy zfs_arc_grow_retry Ns = Ns Sy 0 Ns s Pq uint
If set to a non zero value, it will replace the
.Sy arc_grow_retry
value with this value.
.Sy 0
will disable the throttle.
.
-.It Sy zfs_arc_max Ns = Ns Sy 0 Ns B Pq ulong
+.It Sy zfs_arc_max Ns = Ns Sy 0 Ns B Pq u64
Max size of ARC in bytes.
If
.Sy 0 ,
then the max size of ARC is determined by the amount of system memory installed.
-Under Linux, half of system memory will be used as the limit.
-Under
-.Fx ,
-the larger of
+The larger of
.Sy all_system_memory No \- Sy 1 GiB
and
.Sy 5/8 No \(mu Sy all_system_memory
while running, and reducing it below the current ARC size will not cause
the ARC to shrink without memory pressure to induce shrinking.
.
-.It Sy zfs_arc_meta_adjust_restarts Ns = Ns Sy 4096 Pq ulong
-The number of restart passes to make while scanning the ARC attempting
-the free buffers in order to stay below the
-.Sy fs_arc_meta_limit .
-This value should not need to be tuned but is available to facilitate
-performance analysis.
-.
-.It Sy zfs_arc_meta_limit Ns = Ns Sy 0 Ns B Pq ulong
-The maximum allowed size in bytes that metadata buffers are allowed to
-consume in the ARC.
-When this limit is reached, metadata buffers will be reclaimed,
-even if the overall
-.Sy arc_c_max
-has not been reached.
-It defaults to
-.Sy 0 ,
-which indicates that a percentage based on
-.Sy zfs_arc_meta_limit_percent
-of the ARC may be used for metadata.
-.Pp
-This value my be changed dynamically, except that must be set to an explicit value
-.Pq cannot be set back to Sy 0 .
-.
-.It Sy zfs_arc_meta_limit_percent Ns = Ns Sy 75 Ns % Pq ulong
-Percentage of ARC buffers that can be used for metadata.
-.Pp
-See also
-.Sy zfs_arc_meta_limit ,
-which serves a similar purpose but has a higher priority if nonzero.
-.
-.It Sy zfs_arc_meta_min Ns = Ns Sy 0 Ns B Pq ulong
-The minimum allowed size in bytes that metadata buffers may consume in
-the ARC.
-.
-.It Sy zfs_arc_meta_prune Ns = Ns Sy 10000 Pq int
-The number of dentries and inodes to be scanned looking for entries
-which can be dropped.
-This may be required when the ARC reaches the
-.Sy zfs_arc_meta_limit
-because dentries and inodes can pin buffers in the ARC.
-Increasing this value will cause to dentry and inode caches
-to be pruned more aggressively.
-Setting this value to
-.Sy 0
-will disable pruning the inode and dentry caches.
-.
-.It Sy zfs_arc_meta_strategy Ns = Ns Sy 1 Ns | Ns 0 Pq int
-Define the strategy for ARC metadata buffer eviction (meta reclaim strategy):
-.Bl -tag -compact -offset 4n -width "0 (META_ONLY)"
-.It Sy 0 Pq META_ONLY
-evict only the ARC metadata buffers
-.It Sy 1 Pq BALANCED
-additional data buffers may be evicted if required
-to evict the required number of metadata buffers.
-.El
+.It Sy zfs_arc_meta_balance Ns = Ns Sy 500 Pq uint
+Balance between metadata and data on ghost hits.
+Values above 100 increase metadata caching by proportionally reducing effect
+of ghost data hits on target data/metadata rate.
.
-.It Sy zfs_arc_min Ns = Ns Sy 0 Ns B Pq ulong
+.It Sy zfs_arc_min Ns = Ns Sy 0 Ns B Pq u64
Min size of ARC in bytes.
.No If set to Sy 0 , arc_c_min
will default to consuming the larger of
and
.Sy all_system_memory No / Sy 32 .
.
-.It Sy zfs_arc_min_prefetch_ms Ns = Ns Sy 0 Ns ms Ns Po Ns ≡ Ns 1s Pc Pq int
+.It Sy zfs_arc_min_prefetch_ms Ns = Ns Sy 0 Ns ms Ns Po Ns ≡ Ns 1s Pc Pq uint
Minimum time prefetched blocks are locked in the ARC.
.
-.It Sy zfs_arc_min_prescient_prefetch_ms Ns = Ns Sy 0 Ns ms Ns Po Ns ≡ Ns 6s Pc Pq int
+.It Sy zfs_arc_min_prescient_prefetch_ms Ns = Ns Sy 0 Ns ms Ns Po Ns ≡ Ns 6s Pc Pq uint
Minimum time "prescient prefetched" blocks are locked in the ARC.
These blocks are meant to be prefetched fairly aggressively ahead of
the code that may use them.
Number of missing top-level vdevs which will be allowed during
pool import (only in read-only mode).
.
-.It Sy zfs_max_nvlist_src_size Ns = Sy 0 Pq ulong
+.It Sy zfs_max_nvlist_src_size Ns = Sy 0 Pq u64
Maximum size in bytes allowed to be passed as
.Sy zc_nvlist_src_size
for ioctls on
.Sy 134217728 Ns B Pq 128 MiB
under Linux.
.
-.It Sy zfs_multilist_num_sublists Ns = Ns Sy 0 Pq int
+.It Sy zfs_multilist_num_sublists Ns = Ns Sy 0 Pq uint
To allow more fine-grained locking, each ARC state contains a series
of lists for both data and metadata objects.
Locking is performed at the level of these "sub-lists".
of the target size, and block allocations by
.Em 0.6% .
.
-.It Sy zfs_arc_p_min_shift Ns = Ns Sy 0 Pq int
-If nonzero, this will update
-.Sy arc_p_min_shift Pq default Sy 4
-with the new value.
-.Sy arc_p_min_shift No is used as a shift of Sy arc_c
-when calculating the minumum
-.Sy arc_p No size.
-.
-.It Sy zfs_arc_p_dampener_disable Ns = Ns Sy 1 Ns | Ns 0 Pq int
-Disable
-.Sy arc_p
-adapt dampener, which reduces the maximum single adjustment to
-.Sy arc_p .
-.
-.It Sy zfs_arc_shrink_shift Ns = Ns Sy 0 Pq int
+.It Sy zfs_arc_shrink_shift Ns = Ns Sy 0 Pq uint
If nonzero, this will update
.Sy arc_shrink_shift Pq default Sy 7
with the new value.
The parameter can be set to 0 (zero) to disable the limit,
and only applies on Linux.
.
-.It Sy zfs_arc_sys_free Ns = Ns Sy 0 Ns B Pq ulong
+.It Sy zfs_arc_sys_free Ns = Ns Sy 0 Ns B Pq u64
The target number of bytes the ARC should leave as free memory on the system.
If zero, equivalent to the bigger of
.Sy 512 KiB No and Sy all_system_memory/64 .
(currently 10 checksums over 10 seconds)
or else the daemon may not trigger any action.
.
-.It Sy zfs_commit_timeout_pct Ns = Ns Sy 5 Ns % Pq int
+.It Sy zfs_commit_timeout_pct Ns = Ns Sy 10 Ns % Pq uint
This controls the amount of time that a ZIL block (lwb) will remain "open"
when it isn't "full", and it has a thread waiting for it to be committed to
stable storage.
milliseconds during mapping generation.
Intended for use with the test suite to throttle vdev removal speed.
.
-.It Sy zfs_condense_indirect_obsolete_pct Ns = Ns Sy 25 Ns % Pq int
-Minimum percent of obsolete bytes in vdev mapping required to attempt to condense
+.It Sy zfs_condense_indirect_obsolete_pct Ns = Ns Sy 25 Ns % Pq uint
+Minimum percent of obsolete bytes in vdev mapping required to attempt to
+condense
.Pq see Sy zfs_condense_indirect_vdevs_enable .
Intended for use with the test suite
to facilitate triggering condensing as needed.
bytes of memory and if the obsolete space map object uses more than
.Sy zfs_condense_max_obsolete_bytes
bytes on-disk.
-The condensing process is an attempt to save memory by removing obsolete mappings.
+The condensing process is an attempt to save memory by removing obsolete
+mappings.
.
-.It Sy zfs_condense_max_obsolete_bytes Ns = Ns Sy 1073741824 Ns B Po 1 GiB Pc Pq ulong
+.It Sy zfs_condense_max_obsolete_bytes Ns = Ns Sy 1073741824 Ns B Po 1 GiB Pc Pq u64
Only attempt to condense indirect vdev mappings if the on-disk size
of the obsolete space map object is greater than this number of bytes
.Pq see Sy zfs_condense_indirect_vdevs_enable .
.
-.It Sy zfs_condense_min_mapping_bytes Ns = Ns Sy 131072 Ns B Po 128 KiB Pc Pq ulong
+.It Sy zfs_condense_min_mapping_bytes Ns = Ns Sy 131072 Ns B Po 128 KiB Pc Pq u64
Minimum size vdev mapping to attempt to condense
.Pq see Sy zfs_condense_indirect_vdevs_enable .
.
This setting does not influence debug prints due to
.Sy zfs_flags .
.
-.It Sy zfs_dbgmsg_maxsize Ns = Ns Sy 4194304 Ns B Po 4 MiB Pc Pq int
+.It Sy zfs_dbgmsg_maxsize Ns = Ns Sy 4194304 Ns B Po 4 MiB Pc Pq uint
Maximum size of the internal ZFS debug log.
.
.It Sy zfs_dbuf_state_index Ns = Ns Sy 0 Pq int
to a properly configured fail-over partner.
.El
.
-.It Sy zfs_deadman_checktime_ms Ns = Ns Sy 60000 Ns ms Po 1 min Pc Pq int
+.It Sy zfs_deadman_checktime_ms Ns = Ns Sy 60000 Ns ms Po 1 min Pc Pq u64
Check time in milliseconds.
This defines the frequency at which we check for hung I/O requests
and potentially invoke the
.Sy zfs_deadman_failmode
behavior.
.
-.It Sy zfs_deadman_synctime_ms Ns = Ns Sy 600000 Ns ms Po 10 min Pc Pq ulong
+.It Sy zfs_deadman_synctime_ms Ns = Ns Sy 600000 Ns ms Po 10 min Pc Pq u64
Interval in milliseconds after which the deadman is triggered and also
the interval after which a pool sync operation is considered to be "hung".
Once this limit is exceeded the deadman will be invoked every
.Sy zfs_deadman_checktime_ms
milliseconds until the pool sync completes.
.
-.It Sy zfs_deadman_ziotime_ms Ns = Ns Sy 300000 Ns ms Po 5 min Pc Pq ulong
+.It Sy zfs_deadman_ziotime_ms Ns = Ns Sy 300000 Ns ms Po 5 min Pc Pq u64
Interval in milliseconds after which the deadman is triggered and an
individual I/O operation is considered to be "hung".
As long as the operation remains "hung",
.It Sy zfs_dedup_prefetch Ns = Ns Sy 0 Ns | Ns 1 Pq int
Enable prefetching dedup-ed blocks which are going to be freed.
.
-.It Sy zfs_delay_min_dirty_percent Ns = Ns Sy 60 Ns % Pq int
+.It Sy zfs_delay_min_dirty_percent Ns = Ns Sy 60 Ns % Pq uint
Start to delay each transaction once there is this amount of dirty data,
expressed as a percentage of
.Sy zfs_dirty_data_max .
same object.
.
.It Sy zfs_slow_io_events_per_second Ns = Ns Sy 20 Ns /s Pq int
-Rate limit delay and deadman zevents (which report slow I/O operations) to this many per
+Rate limit delay and deadman zevents (which report slow I/O operations) to this
+many per
second.
.
-.It Sy zfs_unflushed_max_mem_amt Ns = Ns Sy 1073741824 Ns B Po 1 GiB Pc Pq ulong
+.It Sy zfs_unflushed_max_mem_amt Ns = Ns Sy 1073741824 Ns B Po 1 GiB Pc Pq u64
Upper-bound limit for unflushed metadata changes to be held by the
log spacemap in memory, in bytes.
.
-.It Sy zfs_unflushed_max_mem_ppm Ns = Ns Sy 1000 Ns ppm Po 0.1% Pc Pq ulong
+.It Sy zfs_unflushed_max_mem_ppm Ns = Ns Sy 1000 Ns ppm Po 0.1% Pc Pq u64
Part of overall system memory that ZFS allows to be used
for unflushed metadata changes by the log spacemap, in millionths.
.
-.It Sy zfs_unflushed_log_block_max Ns = Ns Sy 131072 Po 128k Pc Pq ulong
+.It Sy zfs_unflushed_log_block_max Ns = Ns Sy 131072 Po 128k Pc Pq u64
Describes the maximum number of log spacemap blocks allowed for each pool.
The default value means that the space in all the log spacemaps
can add up to no more than
This is the reason why this tunable is exposed in terms of blocks rather
than space used.
.
-.It Sy zfs_unflushed_log_block_min Ns = Ns Sy 1000 Pq ulong
+.It Sy zfs_unflushed_log_block_min Ns = Ns Sy 1000 Pq u64
If the number of metaslabs is small and our incoming rate is high,
we could get into a situation that we are flushing all our metaslabs every TXG.
Thus we always allow at least this many log blocks.
.
-.It Sy zfs_unflushed_log_block_pct Ns = Ns Sy 400 Ns % Pq ulong
+.It Sy zfs_unflushed_log_block_pct Ns = Ns Sy 400 Ns % Pq u64
Tunable used to determine the number of blocks that can be used for
the spacemap log, expressed as a percentage of the total number of
unflushed metaslabs in the pool.
.
-.It Sy zfs_unflushed_log_txg_max Ns = Ns Sy 1000 Pq ulong
+.It Sy zfs_unflushed_log_txg_max Ns = Ns Sy 1000 Pq u64
Tunable limiting maximum time in TXGs any metaslab may remain unflushed.
It effectively limits maximum number of unflushed per-TXG spacemap logs
that need to be read after unclean pool export.
will be deleted asynchronously, while smaller files are deleted synchronously.
Decreasing this value will reduce the time spent in an
.Xr unlink 2
-system call, at the expense of a longer delay before the freed space is available.
+system call, at the expense of a longer delay before the freed space is
+available.
+This only applies on Linux.
.
.It Sy zfs_dirty_data_max Ns = Pq int
Determines the dirty space limit in bytes.
.No See Sx ZFS TRANSACTION DELAY .
.Pp
Defaults to
-.Sy physical_ram/4 ,
+.Sy min(physical_ram/4, 4GiB) ,
+or
+.Sy min(physical_ram/4, 1GiB)
+for 32-bit systems.
.
-.It Sy zfs_dirty_data_max_max_percent Ns = Ns Sy 25 Ns % Pq int
+.It Sy zfs_dirty_data_max_max_percent Ns = Ns Sy 25 Ns % Pq uint
Maximum allowable value of
.Sy zfs_dirty_data_max ,
expressed as a percentage of physical RAM.
takes precedence over this one.
.No See Sx ZFS TRANSACTION DELAY .
.
-.It Sy zfs_dirty_data_max_percent Ns = Ns Sy 10 Ns % Pq int
+.It Sy zfs_dirty_data_max_percent Ns = Ns Sy 10 Ns % Pq uint
Determines the dirty space limit, expressed as a percentage of all memory.
Once this limit is exceeded, new writes are halted until space frees up.
The parameter
Subject to
.Sy zfs_dirty_data_max_max .
.
-.It Sy zfs_dirty_data_sync_percent Ns = Ns Sy 20 Ns % Pq int
+.It Sy zfs_dirty_data_sync_percent Ns = Ns Sy 20 Ns % Pq uint
Start syncing out a transaction group if there's at least this much dirty data
.Pq as a percentage of Sy zfs_dirty_data_max .
This should be less than
cleared out after transaction group sync.
Because of some overhead, it should be set at least 2 times the size of
.Sy zfs_dirty_data_max
-.No to prevent harming normal write throughput.
+.No to prevent harming normal write throughput .
It also should be smaller than the size of the slog device if slog is present.
.Pp
Defaults to
results in vector instructions
from the respective CPU instruction set being used.
.
+.It Sy zfs_bclone_enabled Ns = Ns Sy 1 Ns | Ns 0 Pq int
+Enable the experimental block cloning feature.
+If this setting is 0, then even if feature@block_cloning is enabled,
+attempts to clone blocks will act as though the feature is disabled.
+.
+.It Sy zfs_bclone_wait_dirty Ns = Ns Sy 0 Ns | Ns 1 Pq int
+When set to 1 the FICLONE and FICLONERANGE ioctls wait for dirty data to be
+written to disk.
+This allows the clone operation to reliably succeed when a file is
+modified and then immediately cloned.
+For small files this may be slower than making a copy of the file.
+Therefore, this setting defaults to 0 which causes a clone operation to
+immediately fail when encountering a dirty block.
+.
.It Sy zfs_blake3_impl Ns = Ns Sy fastest Pq string
Select a BLAKE3 implementation.
.Pp
.It Sy zfs_free_bpobj_enabled Ns = Ns Sy 1 Ns | Ns 0 Pq int
Enable/disable the processing of the free_bpobj object.
.
-.It Sy zfs_async_block_max_blocks Ns = Ns Sy ULONG_MAX Po unlimited Pc Pq ulong
+.It Sy zfs_async_block_max_blocks Ns = Ns Sy UINT64_MAX Po unlimited Pc Pq u64
Maximum number of blocks freed in a single TXG.
.
-.It Sy zfs_max_async_dedup_frees Ns = Ns Sy 100000 Po 10^5 Pc Pq ulong
+.It Sy zfs_max_async_dedup_frees Ns = Ns Sy 100000 Po 10^5 Pc Pq u64
Maximum number of dedup blocks freed in a single TXG.
.
-.It Sy zfs_vdev_async_read_max_active Ns = Ns Sy 3 Pq int
+.It Sy zfs_vdev_async_read_max_active Ns = Ns Sy 3 Pq uint
Maximum asynchronous read I/O operations active to each device.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_async_read_min_active Ns = Ns Sy 1 Pq int
+.It Sy zfs_vdev_async_read_min_active Ns = Ns Sy 1 Pq uint
Minimum asynchronous read I/O operation active to each device.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_async_write_active_max_dirty_percent Ns = Ns Sy 60 Ns % Pq int
+.It Sy zfs_vdev_async_write_active_max_dirty_percent Ns = Ns Sy 60 Ns % Pq uint
When the pool has more than this much dirty data, use
.Sy zfs_vdev_async_write_max_active
to limit active async writes.
the active I/O limit is linearly interpolated.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_async_write_active_min_dirty_percent Ns = Ns Sy 30 Ns % Pq int
+.It Sy zfs_vdev_async_write_active_min_dirty_percent Ns = Ns Sy 30 Ns % Pq uint
When the pool has less than this much dirty data, use
.Sy zfs_vdev_async_write_min_active
to limit active async writes.
interpolated.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_async_write_max_active Ns = Ns Sy 30 Pq int
+.It Sy zfs_vdev_async_write_max_active Ns = Ns Sy 10 Pq uint
Maximum asynchronous write I/O operations active to each device.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_async_write_min_active Ns = Ns Sy 2 Pq int
+.It Sy zfs_vdev_async_write_min_active Ns = Ns Sy 2 Pq uint
Minimum asynchronous write I/O operations active to each device.
.No See Sx ZFS I/O SCHEDULER .
.Pp
has been shown to improve resilver performance further at a cost of
further increasing latency.
.
-.It Sy zfs_vdev_initializing_max_active Ns = Ns Sy 1 Pq int
+.It Sy zfs_vdev_initializing_max_active Ns = Ns Sy 1 Pq uint
Maximum initializing I/O operations active to each device.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_initializing_min_active Ns = Ns Sy 1 Pq int
+.It Sy zfs_vdev_initializing_min_active Ns = Ns Sy 1 Pq uint
Minimum initializing I/O operations active to each device.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_max_active Ns = Ns Sy 1000 Pq int
+.It Sy zfs_vdev_max_active Ns = Ns Sy 1000 Pq uint
The maximum number of I/O operations active to each device.
Ideally, this will be at least the sum of each queue's
.Sy max_active .
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_rebuild_max_active Ns = Ns Sy 3 Pq int
+.It Sy zfs_vdev_open_timeout_ms Ns = Ns Sy 1000 Pq uint
+Timeout value to wait before determining a device is missing
+during import.
+This is helpful for transient missing paths due
+to links being briefly removed and recreated in response to
+udev events.
+.
+.It Sy zfs_vdev_rebuild_max_active Ns = Ns Sy 3 Pq uint
Maximum sequential resilver I/O operations active to each device.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_rebuild_min_active Ns = Ns Sy 1 Pq int
+.It Sy zfs_vdev_rebuild_min_active Ns = Ns Sy 1 Pq uint
Minimum sequential resilver I/O operations active to each device.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_removal_max_active Ns = Ns Sy 2 Pq int
+.It Sy zfs_vdev_removal_max_active Ns = Ns Sy 2 Pq uint
Maximum removal I/O operations active to each device.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_removal_min_active Ns = Ns Sy 1 Pq int
+.It Sy zfs_vdev_removal_min_active Ns = Ns Sy 1 Pq uint
Minimum removal I/O operations active to each device.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_scrub_max_active Ns = Ns Sy 2 Pq int
+.It Sy zfs_vdev_scrub_max_active Ns = Ns Sy 2 Pq uint
Maximum scrub I/O operations active to each device.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_scrub_min_active Ns = Ns Sy 1 Pq int
+.It Sy zfs_vdev_scrub_min_active Ns = Ns Sy 1 Pq uint
Minimum scrub I/O operations active to each device.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_sync_read_max_active Ns = Ns Sy 10 Pq int
+.It Sy zfs_vdev_sync_read_max_active Ns = Ns Sy 10 Pq uint
Maximum synchronous read I/O operations active to each device.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_sync_read_min_active Ns = Ns Sy 10 Pq int
+.It Sy zfs_vdev_sync_read_min_active Ns = Ns Sy 10 Pq uint
Minimum synchronous read I/O operations active to each device.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_sync_write_max_active Ns = Ns Sy 10 Pq int
+.It Sy zfs_vdev_sync_write_max_active Ns = Ns Sy 10 Pq uint
Maximum synchronous write I/O operations active to each device.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_sync_write_min_active Ns = Ns Sy 10 Pq int
+.It Sy zfs_vdev_sync_write_min_active Ns = Ns Sy 10 Pq uint
Minimum synchronous write I/O operations active to each device.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_trim_max_active Ns = Ns Sy 2 Pq int
+.It Sy zfs_vdev_trim_max_active Ns = Ns Sy 2 Pq uint
Maximum trim/discard I/O operations active to each device.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_trim_min_active Ns = Ns Sy 1 Pq int
+.It Sy zfs_vdev_trim_min_active Ns = Ns Sy 1 Pq uint
Minimum trim/discard I/O operations active to each device.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_nia_delay Ns = Ns Sy 5 Pq int
+.It Sy zfs_vdev_nia_delay Ns = Ns Sy 5 Pq uint
For non-interactive I/O (scrub, resilver, removal, initialize and rebuild),
the number of concurrently-active I/O operations is limited to
.Sy zfs_*_min_active ,
.Sy zfs_*_max_active .
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_nia_credit Ns = Ns Sy 5 Pq int
+.It Sy zfs_vdev_nia_credit Ns = Ns Sy 5 Pq uint
Some HDDs tend to prioritize sequential I/O so strongly, that concurrent
random I/O latency reaches several seconds.
On some HDDs this happens even if sequential I/O operations
within a reasonable amount of time.
.No See Sx ZFS I/O SCHEDULER .
.
-.It Sy zfs_vdev_queue_depth_pct Ns = Ns Sy 1000 Ns % Pq int
+.It Sy zfs_vdev_queue_depth_pct Ns = Ns Sy 1000 Ns % Pq uint
Maximum number of queued allocations per top-level vdev expressed as
a percentage of
.Sy zfs_vdev_async_write_max_active ,
Also see
.Sy zio_dva_throttle_enabled .
.
+.It Sy zfs_vdev_def_queue_depth Ns = Ns Sy 32 Pq uint
+Default queue depth for each vdev IO allocator.
+Higher values allow for better coalescing of sequential writes before sending
+them to the disk, but can increase transaction commit times.
+.
+.It Sy zfs_vdev_failfast_mask Ns = Ns Sy 1 Pq uint
+Defines if the driver should retire on a given error type.
+The following options may be bitwise-ored together:
+.TS
+box;
+lbz r l l .
+ Value Name Description
+_
+ 1 Device No driver retries on device errors
+ 2 Transport No driver retries on transport errors.
+ 4 Driver No driver retries on driver errors.
+.TE
+.
+.It Sy zfs_vdev_disk_max_segs Ns = Ns Sy 0 Pq uint
+Maximum number of segments to add to a BIO (min 4).
+If this is higher than the maximum allowed by the device queue or the kernel
+itself, it will be clamped.
+Setting it to zero will cause the kernel's ideal size to be used.
+This parameter only applies on Linux.
+This parameter is ignored if
+.Sy zfs_vdev_disk_classic Ns = Ns Sy 1 .
+.
+.It Sy zfs_vdev_disk_classic Ns = Ns Sy 0 Ns | Ns 1 Pq uint
+If set to 1, OpenZFS will submit IO to Linux using the method it used in 2.2
+and earlier.
+This "classic" method has known issues with highly fragmented IO requests and
+is slower on many workloads, but it has been in use for many years and is known
+to be very stable.
+If you set this parameter, please also open a bug report why you did so,
+including the workload involved and any error messages.
+.Pp
+This parameter and the classic submission method will be removed once we have
+total confidence in the new method.
+.Pp
+This parameter only applies on Linux, and can only be set at module load time.
+.
.It Sy zfs_expire_snapshot Ns = Ns Sy 300 Ns s Pq int
Time before expiring
.Pa .zfs/snapshot .
.TS
box;
lbz r l l .
- Value Symbolic Name Description
+ Value Name Description
_
1 ZFS_DEBUG_DPRINTF Enable dprintf entries in the debug log.
* 2 ZFS_DEBUG_DBUF_VERIFY Enable extra dbuf verifications.
* 4 ZFS_DEBUG_DNODE_VERIFY Enable extra dnode verifications.
8 ZFS_DEBUG_SNAPNAMES Enable snapshot name verification.
- 16 ZFS_DEBUG_MODIFY Check for illegally modified ARC buffers.
+* 16 ZFS_DEBUG_MODIFY Check for illegally modified ARC buffers.
64 ZFS_DEBUG_ZIO_FREE Enable verification of block frees.
128 ZFS_DEBUG_HISTOGRAM_VERIFY Enable extra spacemap histogram verifications.
256 ZFS_DEBUG_METASLAB_VERIFY Verify space accounting on disk matches in-memory \fBrange_trees\fP.
4096 ZFS_DEBUG_LOG_SPACEMAP Verify that the log summary is consistent with the spacemap log
and enable \fBzfs_dbgmsgs\fP for metaslab loading and flushing.
.TE
-.Sy \& * No Requires debug build.
+.Sy \& * No Requires debug build .
.
.It Sy zfs_btree_verify_intensity Ns = Ns Sy 0 Pq uint
Enables btree verification.
4 Verify element order. (expensive)
* 5 Verify unused memory is poisoned. (expensive)
.TE
-.Sy \& * No Requires debug build.
+.Sy \& * No Requires debug build .
.
.It Sy zfs_free_leak_on_eio Ns = Ns Sy 0 Ns | Ns 1 Pq int
If destroy encounters an
so that there is no possibility of
leaking space in the "partial temporary" failure case.
.
-.It Sy zfs_free_min_time_ms Ns = Ns Sy 1000 Ns ms Po 1s Pc Pq int
+.It Sy zfs_free_min_time_ms Ns = Ns Sy 1000 Ns ms Po 1s Pc Pq uint
During a
.Nm zfs Cm destroy
operation using the
feature,
a minimum of this much time will be spent working on freeing blocks per TXG.
.
-.It Sy zfs_obsolete_min_time_ms Ns = Ns Sy 500 Ns ms Pq int
+.It Sy zfs_obsolete_min_time_ms Ns = Ns Sy 500 Ns ms Pq uint
Similar to
.Sy zfs_free_min_time_ms ,
but for cleanup of old indirection records for removed vdevs.
.
-.It Sy zfs_immediate_write_sz Ns = Ns Sy 32768 Ns B Po 32 KiB Pc Pq long
+.It Sy zfs_immediate_write_sz Ns = Ns Sy 32768 Ns B Po 32 KiB Pc Pq s64
Largest data block to write to the ZIL.
Larger blocks will be treated as if the dataset being written to had the
.Sy logbias Ns = Ns Sy throughput
property set.
.
-.It Sy zfs_initialize_value Ns = Ns Sy 16045690984833335022 Po 0xDEADBEEFDEADBEEE Pc Pq ulong
+.It Sy zfs_initialize_value Ns = Ns Sy 16045690984833335022 Po 0xDEADBEEFDEADBEEE Pc Pq u64
Pattern written to vdev free space by
.Xr zpool-initialize 8 .
.
-.It Sy zfs_initialize_chunk_size Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq ulong
+.It Sy zfs_initialize_chunk_size Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq u64
Size of writes used by
.Xr zpool-initialize 8 .
This option is used by the test suite.
.
-.It Sy zfs_livelist_max_entries Ns = Ns Sy 500000 Po 5*10^5 Pc Pq ulong
+.It Sy zfs_livelist_max_entries Ns = Ns Sy 500000 Po 5*10^5 Pc Pq u64
The threshold size (in block pointers) at which we create a new sub-livelist.
Larger sublists are more costly from a memory perspective but the fewer
sublists there are, the lower the cost of insertion.
.Fn spa_livelist_condense_cb .
This option is used by the test suite to trigger race conditions.
.
-.It Sy zfs_lua_max_instrlimit Ns = Ns Sy 100000000 Po 10^8 Pc Pq ulong
+.It Sy zfs_lua_max_instrlimit Ns = Ns Sy 100000000 Po 10^8 Pc Pq u64
The maximum execution time limit that can be set for a ZFS channel program,
specified as a number of Lua instructions.
.
-.It Sy zfs_lua_max_memlimit Ns = Ns Sy 104857600 Po 100 MiB Pc Pq ulong
+.It Sy zfs_lua_max_memlimit Ns = Ns Sy 104857600 Po 100 MiB Pc Pq u64
The maximum memory limit that can be set for a ZFS channel program, specified
in bytes.
.
This value can be tuned temporarily to
fix existing datasets that exceed the predefined limit.
.
-.It Sy zfs_max_log_walking Ns = Ns Sy 5 Pq ulong
+.It Sy zfs_max_log_walking Ns = Ns Sy 5 Pq u64
The number of past TXGs that the flushing algorithm of the log spacemap
feature uses to estimate incoming log blocks.
.
-.It Sy zfs_max_logsm_summary_length Ns = Ns Sy 10 Pq ulong
+.It Sy zfs_max_logsm_summary_length Ns = Ns Sy 10 Pq u64
Maximum number of rows allowed in the summary of the spacemap log.
.
-.It Sy zfs_max_recordsize Ns = Ns Sy 16777216 Po 16 MiB Pc Pq int
+.It Sy zfs_max_recordsize Ns = Ns Sy 16777216 Po 16 MiB Pc Pq uint
We currently support block sizes from
.Em 512 Po 512 B Pc No to Em 16777216 Po 16 MiB Pc .
The benefits of larger blocks, and thus larger I/O,
Allow datasets received with redacted send/receive to be mounted.
Normally disabled because these datasets may be missing key data.
.
-.It Sy zfs_min_metaslabs_to_flush Ns = Ns Sy 1 Pq ulong
+.It Sy zfs_min_metaslabs_to_flush Ns = Ns Sy 1 Pq u64
Minimum number of metaslabs to flush per dirty TXG.
.
-.It Sy zfs_metaslab_fragmentation_threshold Ns = Ns Sy 70 Ns % Pq int
+.It Sy zfs_metaslab_fragmentation_threshold Ns = Ns Sy 70 Ns % Pq uint
Allow metaslabs to keep their active state as long as their fragmentation
percentage is no more than this value.
An active metaslab that exceeds this threshold
will no longer keep its active status allowing better metaslabs to be selected.
.
-.It Sy zfs_mg_fragmentation_threshold Ns = Ns Sy 95 Ns % Pq int
+.It Sy zfs_mg_fragmentation_threshold Ns = Ns Sy 95 Ns % Pq uint
Metaslab groups are considered eligible for allocations if their
fragmentation metric (measured as a percentage) is less than or equal to
this value.
skipped unless all metaslab groups within the metaslab class have also
crossed this threshold.
.
-.It Sy zfs_mg_noalloc_threshold Ns = Ns Sy 0 Ns % Pq int
+.It Sy zfs_mg_noalloc_threshold Ns = Ns Sy 0 Ns % Pq uint
Defines a threshold at which metaslab groups should be eligible for allocations.
The value is expressed as a percentage of free space
beyond which a metaslab group is always eligible for allocations.
allocations.
The default value of
.Sy 0
-disables the feature and causes all metaslab groups to be eligible for allocations.
+disables the feature and causes all metaslab groups to be eligible for
+allocations.
.Pp
This parameter allows one to deal with pools having heavily imbalanced
vdevs such as would be the case when a new vdev has been added.
If enabled, ZFS will place user data indirect blocks
into the special allocation class.
.
-.It Sy zfs_multihost_history Ns = Ns Sy 0 Pq int
-Historical statistics for this many latest multihost updates will be available in
+.It Sy zfs_multihost_history Ns = Ns Sy 0 Pq uint
+Historical statistics for this many latest multihost updates will be available
+in
.Pa /proc/spl/kstat/zfs/ Ns Ao Ar pool Ac Ns Pa /multihost .
.
-.It Sy zfs_multihost_interval Ns = Ns Sy 1000 Ns ms Po 1 s Pc Pq ulong
+.It Sy zfs_multihost_interval Ns = Ns Sy 1000 Ns ms Po 1 s Pc Pq u64
Used to control the frequency of multihost writes which are performed when the
.Sy multihost
pool property is on.
.Nm zfs Cm send
or other data crawling operations.
.
-.It Sy zfs_traverse_indirect_prefetch_limit Ns = Ns Sy 32 Pq int
+.It Sy zfs_traverse_indirect_prefetch_limit Ns = Ns Sy 32 Pq uint
The number of blocks pointed by indirect (non-L0) block which should be
prefetched during a pool traversal, like
.Nm zfs Cm send
or other data crawling operations.
.
-.It Sy zfs_per_txg_dirty_frees_percent Ns = Ns Sy 5 Ns % Pq ulong
+.It Sy zfs_per_txg_dirty_frees_percent Ns = Ns Sy 30 Ns % Pq u64
Control percentage of dirtied indirect blocks from frees allowed into one TXG.
After this threshold is crossed, additional frees will wait until the next TXG.
-.Sy 0 No disables this throttle.
+.Sy 0 No disables this throttle .
.
.It Sy zfs_prefetch_disable Ns = Ns Sy 0 Ns | Ns 1 Pq int
Disable predictive prefetch.
May be unset after the ZFS modules have been loaded to initialize the QAT
hardware as long as support is compiled in and the QAT driver is present.
.
-.It Sy zfs_vnops_read_chunk_size Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq long
+.It Sy zfs_vnops_read_chunk_size Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq u64
Bytes to read per chunk.
.
-.It Sy zfs_read_history Ns = Ns Sy 0 Pq int
+.It Sy zfs_read_history Ns = Ns Sy 0 Pq uint
Historical statistics for this many latest reads will be available in
.Pa /proc/spl/kstat/zfs/ Ns Ao Ar pool Ac Ns Pa /reads .
.
.It Sy zfs_read_history_hits Ns = Ns Sy 0 Ns | Ns 1 Pq int
Include cache hits in read history
.
-.It Sy zfs_rebuild_max_segment Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq ulong
+.It Sy zfs_rebuild_max_segment Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq u64
Maximum read segment size to issue when sequentially resilvering a
top-level vdev.
.
resilvered.
This is enabled by default and strongly recommended.
.
-.It Sy zfs_rebuild_vdev_limit Ns = Ns Sy 33554432 Ns B Po 32 MiB Pc Pq ulong
+.It Sy zfs_rebuild_vdev_limit Ns = Ns Sy 67108864 Ns B Po 64 MiB Pc Pq u64
Maximum amount of I/O that can be concurrently issued for a sequential
resilver per leaf device, given in bytes.
.
This should only be used as a last resort when the
pool cannot be returned to a healthy state prior to removing the device.
.
-.It Sy zfs_removal_suspend_progress Ns = Ns Sy 0 Ns | Ns 1 Pq int
+.It Sy zfs_removal_suspend_progress Ns = Ns Sy 0 Ns | Ns 1 Pq uint
This is used by the test suite so that it can ensure that certain actions
happen while in the middle of a removal.
.
-.It Sy zfs_remove_max_segment Ns = Ns Sy 16777216 Ns B Po 16 MiB Pc Pq int
+.It Sy zfs_remove_max_segment Ns = Ns Sy 16777216 Ns B Po 16 MiB Pc Pq uint
The largest contiguous segment that we will attempt to allocate when removing
a device.
If there is a performance problem with attempting to allocate large blocks,
feature, causing an operation that would start a resilver to
immediately restart the one in progress.
.
-.It Sy zfs_resilver_min_time_ms Ns = Ns Sy 3000 Ns ms Po 3 s Pc Pq int
+.It Sy zfs_resilver_min_time_ms Ns = Ns Sy 3000 Ns ms Po 3 s Pc Pq uint
Resilvers are processed by the sync thread.
While resilvering, it will spend at least this much time
working on a resilver between TXG flushes.
Intended to be used during pool repair or recovery to
stop resilvering when the pool is next imported.
.
-.It Sy zfs_scrub_min_time_ms Ns = Ns Sy 1000 Ns ms Po 1 s Pc Pq int
+.It Sy zfs_scrub_after_expand Ns = Ns Sy 1 Ns | Ns 0 Pq int
+Automatically start a pool scrub after a RAIDZ expansion completes
+in order to verify the checksums of all blocks which have been
+copied during the expansion.
+This is enabled by default and strongly recommended.
+.
+.It Sy zfs_scrub_min_time_ms Ns = Ns Sy 1000 Ns ms Po 1 s Pc Pq uint
Scrubs are processed by the sync thread.
While scrubbing, it will spend at least this much time
working on a scrub between TXG flushes.
.
-.It Sy zfs_scan_checkpoint_intval Ns = Ns Sy 7200 Ns s Po 2 hour Pc Pq int
+.It Sy zfs_scrub_error_blocks_per_txg Ns = Ns Sy 4096 Pq uint
+Error blocks to be scrubbed in one txg.
+.
+.It Sy zfs_scan_checkpoint_intval Ns = Ns Sy 7200 Ns s Po 2 hour Pc Pq uint
To preserve progress across reboots, the sequential scan algorithm periodically
needs to stop metadata scanning and issue all the verification I/O to disk.
The frequency of this flushing is determined by this tunable.
.
-.It Sy zfs_scan_fill_weight Ns = Ns Sy 3 Pq int
+.It Sy zfs_scan_fill_weight Ns = Ns Sy 3 Pq uint
This tunable affects how scrub and resilver I/O segments are ordered.
A higher number indicates that we care more about how filled in a segment is,
while a lower number indicates we care more about the size of the extent without
considering the gaps within a segment.
This value is only tunable upon module insertion.
-Changing the value afterwards will have no effect on scrub or resilver performance.
+Changing the value afterwards will have no effect on scrub or resilver
+performance.
.
-.It Sy zfs_scan_issue_strategy Ns = Ns Sy 0 Pq int
+.It Sy zfs_scan_issue_strategy Ns = Ns Sy 0 Pq uint
Determines the order that data will be verified while scrubbing or resilvering:
.Bl -tag -compact -offset 4n -width "a"
.It Sy 1
to coalesce and increase the segment size.
.It Sy 0
.No Use strategy Sy 1 No during normal verification
-.No and strategy Sy 2 No while taking a checkpoint.
+.No and strategy Sy 2 No while taking a checkpoint .
.El
.
.It Sy zfs_scan_legacy Ns = Ns Sy 0 Ns | Ns 1 Pq int
Changing this value will not
affect scrubs or resilvers that are already in progress.
.
-.It Sy zfs_scan_mem_lim_fact Ns = Ns Sy 20 Ns ^-1 Pq int
+.It Sy zfs_scan_mem_lim_fact Ns = Ns Sy 20 Ns ^-1 Pq uint
Maximum fraction of RAM used for I/O sorting by sequential scan algorithm.
This tunable determines the hard limit for I/O sorting memory usage.
When the hard limit is reached we stop scanning metadata and start issuing
data verification I/O.
This is done until we get below the soft limit.
.
-.It Sy zfs_scan_mem_lim_soft_fact Ns = Ns Sy 20 Ns ^-1 Pq int
+.It Sy zfs_scan_mem_lim_soft_fact Ns = Ns Sy 20 Ns ^-1 Pq uint
The fraction of the hard limit used to determined the soft limit for I/O sorting
by the sequential scan algorithm.
When we cross this limit from below no action is taken.
-When we cross this limit from above it is because we are issuing verification I/O.
+When we cross this limit from above it is because we are issuing verification
+I/O.
In this case (unless the metadata scan is done) we stop issuing verification I/O
and start scanning metadata again until we get to the hard limit.
.
+.It Sy zfs_scan_report_txgs Ns = Ns Sy 0 Ns | Ns 1 Pq uint
+When reporting resilver throughput and estimated completion time use the
+performance observed over roughly the last
+.Sy zfs_scan_report_txgs
+TXGs.
+When set to zero performance is calculated over the time between checkpoints.
+.
.It Sy zfs_scan_strict_mem_lim Ns = Ns Sy 0 Ns | Ns 1 Pq int
Enforce tight memory limits on pool scans when a sequential scan is in progress.
When disabled, the memory limit may be exceeded by fast disks.
Freezes a scrub/resilver in progress without actually pausing it.
Intended for testing/debugging.
.
-.It Sy zfs_scan_vdev_limit Ns = Ns Sy 4194304 Ns B Po 4 MiB Pc Pq int
+.It Sy zfs_scan_vdev_limit Ns = Ns Sy 16777216 Ns B Po 16 MiB Pc Pq int
Maximum amount of data that can be concurrently issued at once for scrubs and
resilvers per leaf device, given in bytes.
.
Including unmodified copies of the spill blocks creates a backwards-compatible
stream which will recreate a spill block if it was incorrectly removed.
.
-.It Sy zfs_send_no_prefetch_queue_ff Ns = Ns Sy 20 Ns ^\-1 Pq int
+.It Sy zfs_send_no_prefetch_queue_ff Ns = Ns Sy 20 Ns ^\-1 Pq uint
The fill fraction of the
.Nm zfs Cm send
internal queues.
The fill fraction controls the timing with which internal threads are woken up.
.
-.It Sy zfs_send_no_prefetch_queue_length Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq int
+.It Sy zfs_send_no_prefetch_queue_length Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq uint
The maximum number of bytes allowed in
.Nm zfs Cm send Ns 's
internal queues.
.
-.It Sy zfs_send_queue_ff Ns = Ns Sy 20 Ns ^\-1 Pq int
+.It Sy zfs_send_queue_ff Ns = Ns Sy 20 Ns ^\-1 Pq uint
The fill fraction of the
.Nm zfs Cm send
prefetch queue.
The fill fraction controls the timing with which internal threads are woken up.
.
-.It Sy zfs_send_queue_length Ns = Ns Sy 16777216 Ns B Po 16 MiB Pc Pq int
+.It Sy zfs_send_queue_length Ns = Ns Sy 16777216 Ns B Po 16 MiB Pc Pq uint
The maximum number of bytes allowed that will be prefetched by
.Nm zfs Cm send .
This value must be at least twice the maximum block size in use.
.
-.It Sy zfs_recv_queue_ff Ns = Ns Sy 20 Ns ^\-1 Pq int
+.It Sy zfs_recv_queue_ff Ns = Ns Sy 20 Ns ^\-1 Pq uint
The fill fraction of the
.Nm zfs Cm receive
queue.
The fill fraction controls the timing with which internal threads are woken up.
.
-.It Sy zfs_recv_queue_length Ns = Ns Sy 16777216 Ns B Po 16 MiB Pc Pq int
+.It Sy zfs_recv_queue_length Ns = Ns Sy 16777216 Ns B Po 16 MiB Pc Pq uint
The maximum number of bytes allowed in the
.Nm zfs Cm receive
queue.
This value must be at least twice the maximum block size in use.
.
-.It Sy zfs_recv_write_batch_size Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq int
+.It Sy zfs_recv_write_batch_size Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq uint
The maximum amount of data, in bytes, that
.Nm zfs Cm receive
will write in one DMU transaction.
terminated instead it moves on to the next record.
.El
.
-.It Sy zfs_override_estimate_recordsize Ns = Ns Sy 0 Ns | Ns 1 Pq ulong
+.It Sy zfs_override_estimate_recordsize Ns = Ns Sy 0 Ns | Ns 1 Pq uint
Setting this variable overrides the default logic for estimating block
sizes when doing a
.Nm zfs Cm send .
Override this value if most data in your dataset is not of that size
and you require accurate zfs send size estimates.
.
-.It Sy zfs_sync_pass_deferred_free Ns = Ns Sy 2 Pq int
+.It Sy zfs_sync_pass_deferred_free Ns = Ns Sy 2 Pq uint
Flushing of data to disk is done in passes.
Defer frees starting in this pass.
.
Maximum memory used for prefetching a checkpoint's space map on each
vdev while discarding the checkpoint.
.
-.It Sy zfs_special_class_metadata_reserve_pct Ns = Ns Sy 25 Ns % Pq int
+.It Sy zfs_special_class_metadata_reserve_pct Ns = Ns Sy 25 Ns % Pq uint
Only allow small data blocks to be allocated on the special and dedup vdev
-types when the available free space percentage on these vdevs exceeds this value.
+types when the available free space percentage on these vdevs exceeds this
+value.
This ensures reserved space is available for pool metadata as the
special vdevs approach capacity.
.
-.It Sy zfs_sync_pass_dont_compress Ns = Ns Sy 8 Pq int
+.It Sy zfs_sync_pass_dont_compress Ns = Ns Sy 8 Pq uint
Starting in this sync pass, disable compression (including of metadata).
With the default setting, in practice, we don't have this many sync passes,
so this has no effect.
The
.Em 128 KiB
allocations are especially detrimental to performance
-on highly fragmented systems, which may have very few free segments of this size,
+on highly fragmented systems, which may have very few free segments of this
+size,
and may need to load new metaslabs to satisfy these allocations.
.
-.It Sy zfs_sync_pass_rewrite Ns = Ns Sy 2 Pq int
+.It Sy zfs_sync_pass_rewrite Ns = Ns Sy 2 Pq uint
Rewrite new block pointers starting in this pass.
.
-.It Sy zfs_sync_taskq_batch_pct Ns = Ns Sy 75 Ns % Pq int
-This controls the number of threads used by
-.Sy dp_sync_taskq .
-The default value of
-.Sy 75%
-will create a maximum of one thread per CPU.
-.
.It Sy zfs_trim_extent_bytes_max Ns = Ns Sy 134217728 Ns B Po 128 MiB Pc Pq uint
Maximum size of TRIM command.
-Larger ranges will be split into chunks no larger than this value before issuing.
+Larger ranges will be split into chunks no larger than this value before
+issuing.
.
.It Sy zfs_trim_extent_bytes_min Ns = Ns Sy 32768 Ns B Po 32 KiB Pc Pq uint
Minimum size of TRIM commands.
.
.It Sy zfs_trim_metaslab_skip Ns = Ns Sy 0 Ns | Ns 1 Pq uint
Skip uninitialized metaslabs during the TRIM process.
-This option is useful for pools constructed from large thinly-provisioned devices
+This option is useful for pools constructed from large thinly-provisioned
+devices
where TRIM operations are slow.
As a pool ages, an increasing fraction of the pool's metaslabs
will be initialized, progressively degrading the usefulness of this option.
before the recently trimmed space is available for use by the device.
.Pp
Increasing this value will allow frees to be aggregated for a longer time.
-This will result is larger TRIM operations and potentially increased memory usage.
+This will result is larger TRIM operations and potentially increased memory
+usage.
Decreasing this value will have the opposite effect.
The default of
.Sy 32
was determined to be a reasonable compromise.
.
-.It Sy zfs_txg_history Ns = Ns Sy 0 Pq int
+.It Sy zfs_txg_history Ns = Ns Sy 0 Pq uint
Historical statistics for this many latest TXGs will be available in
.Pa /proc/spl/kstat/zfs/ Ns Ao Ar pool Ac Ns Pa /TXGs .
.
-.It Sy zfs_txg_timeout Ns = Ns Sy 5 Ns s Pq int
-Flush dirty data to disk at least every this many seconds (maximum TXG duration).
-.
-.It Sy zfs_vdev_aggregate_trim Ns = Ns Sy 0 Ns | Ns 1 Pq int
-Allow TRIM I/O operations to be aggregated.
-This is normally not helpful because the extents to be trimmed
-will have been already been aggregated by the metaslab.
-This option is provided for debugging and performance analysis.
+.It Sy zfs_txg_timeout Ns = Ns Sy 5 Ns s Pq uint
+Flush dirty data to disk at least every this many seconds (maximum TXG
+duration).
.
-.It Sy zfs_vdev_aggregation_limit Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq int
+.It Sy zfs_vdev_aggregation_limit Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq uint
Max vdev I/O aggregation size.
.
-.It Sy zfs_vdev_aggregation_limit_non_rotating Ns = Ns Sy 131072 Ns B Po 128 KiB Pc Pq int
+.It Sy zfs_vdev_aggregation_limit_non_rotating Ns = Ns Sy 131072 Ns B Po 128 KiB Pc Pq uint
Max vdev I/O aggregation size for non-rotating media.
.
-.It Sy zfs_vdev_cache_bshift Ns = Ns Sy 16 Po 64 KiB Pc Pq int
-Shift size to inflate reads to.
-.
-.It Sy zfs_vdev_cache_max Ns = Ns Sy 16384 Ns B Po 16 KiB Pc Pq int
-Inflate reads smaller than this value to meet the
-.Sy zfs_vdev_cache_bshift
-size
-.Pq default Sy 64 KiB .
-.
-.It Sy zfs_vdev_cache_size Ns = Ns Sy 0 Pq int
-Total size of the per-disk cache in bytes.
-.Pp
-Currently this feature is disabled, as it has been found to not be helpful
-for performance and in some cases harmful.
-.
.It Sy zfs_vdev_mirror_rotating_inc Ns = Ns Sy 0 Pq int
A number by which the balancing algorithm increments the load calculation for
the purpose of selecting the least busy mirror member when an I/O operation
.
.It Sy zfs_vdev_mirror_non_rotating_seek_inc Ns = Ns Sy 1 Pq int
A number by which the balancing algorithm increments the load calculation for
-the purpose of selecting the least busy mirror member when an I/O operation lacks
+the purpose of selecting the least busy mirror member when an I/O operation
+lacks
locality as defined by the
.Sy zfs_vdev_mirror_rotating_seek_offset .
Operations within this that are not immediately following the previous operation
are incremented by half.
.
-.It Sy zfs_vdev_read_gap_limit Ns = Ns Sy 32768 Ns B Po 32 KiB Pc Pq int
+.It Sy zfs_vdev_read_gap_limit Ns = Ns Sy 32768 Ns B Po 32 KiB Pc Pq uint
Aggregate read I/O operations if the on-disk gap between them is within this
threshold.
.
-.It Sy zfs_vdev_write_gap_limit Ns = Ns Sy 4096 Ns B Po 4 KiB Pc Pq int
+.It Sy zfs_vdev_write_gap_limit Ns = Ns Sy 4096 Ns B Po 4 KiB Pc Pq uint
Aggregate write I/O operations if the on-disk gap between them is within this
threshold.
.
.Sy DEPRECATED .
Prints warning to kernel log for compatibility.
.
-.It Sy zfs_zevent_len_max Ns = Ns Sy 512 Pq int
+.It Sy zfs_zevent_len_max Ns = Ns Sy 512 Pq uint
Max event queue length.
Events in the queue can be viewed with
.Xr zpool-events 8 .
.Sy 100%
will create a maximum of one thread per cpu.
.
-.It Sy zil_maxblocksize Ns = Ns Sy 131072 Ns B Po 128 KiB Pc Pq int
+.It Sy zil_maxblocksize Ns = Ns Sy 131072 Ns B Po 128 KiB Pc Pq uint
This sets the maximum block size used by the ZIL.
On very fragmented pools, lowering this
.Pq typically to Sy 36 KiB
can improve performance.
.
+.It Sy zil_maxcopied Ns = Ns Sy 7680 Ns B Po 7.5 KiB Pc Pq uint
+This sets the maximum number of write bytes logged via WR_COPIED.
+It tunes a tradeoff between additional memory copy and possibly worse log
+space efficiency vs additional range lock/unlock.
+.
.It Sy zil_nocacheflush Ns = Ns Sy 0 Ns | Ns 1 Pq int
Disable the cache flush commands that are normally sent to disk by
the ZIL after an LWB write has completed.
Disable intent logging replay.
Can be disabled for recovery from corrupted ZIL.
.
-.It Sy zil_slog_bulk Ns = Ns Sy 786432 Ns B Po 768 KiB Pc Pq ulong
+.It Sy zil_slog_bulk Ns = Ns Sy 67108864 Ns B Po 64 MiB Pc Pq u64
Limit SLOG write size per commit executed with synchronous priority.
Any writes above that will be executed with lower (asynchronous) priority
to limit potential SLOG device abuse by single active ZIL writer.
code for this record type.
The tunable has no effect if the feature is disabled.
.
-.It Sy zfs_embedded_slog_min_ms Ns = Ns Sy 64 Pq int
+.It Sy zfs_embedded_slog_min_ms Ns = Ns Sy 64 Pq uint
Usually, one metaslab from each normal-class vdev is dedicated for use by
the ZIL to log synchronous writes.
However, if there are fewer than
.Sy zfs_embedded_slog_min_ms
metaslabs in the vdev, this functionality is disabled.
-This ensures that we don't set aside an unreasonable amount of space for the ZIL.
+This ensures that we don't set aside an unreasonable amount of space for the
+ZIL.
.
-.It Sy zstd_earlyabort_pass Ns = Ns Sy 1 Pq int
+.It Sy zstd_earlyabort_pass Ns = Ns Sy 1 Pq uint
Whether heuristic for detection of incompressible data with zstd levels >= 3
using LZ4 and zstd-1 passes is enabled.
.
-.It Sy zstd_abort_size Ns = Ns Sy 131072 Pq int
+.It Sy zstd_abort_size Ns = Ns Sy 131072 Pq uint
Minimal uncompressed size (inclusive) of a record before the early abort
heuristic will be attempted.
.
.Sy 0 ,
generate a system-dependent value close to 6 threads per taskq.
.
+.It Sy zio_taskq_wr_iss_ncpus Ns = Ns Sy 0 Pq uint
+Determines the number of CPUs to run write issue taskqs.
+.Pp
+When 0 (the default), the value to use is computed internally
+as the number of actual CPUs in the system divided by the
+.Sy spa_num_allocators
+value.
+.
+.It Sy zio_taskq_read Ns = Ns Sy fixed,1,8 null scale null Pq charp
+Set the queue and thread configuration for the IO read queues.
+This is an advanced debugging parameter.
+Don't change this unless you understand what it does.
+.
+.It Sy zio_taskq_write Ns = Ns Sy sync fixed,1,5 scale fixed,1,5 Pq charp
+Set the queue and thread configuration for the IO write queues.
+This is an advanced debugging parameter.
+Don't change this unless you understand what it does.
+.
.It Sy zvol_inhibit_dev Ns = Ns Sy 0 Ns | Ns 1 Pq uint
Do not create zvol device nodes.
This may slightly improve startup time on
.It Sy zvol_major Ns = Ns Sy 230 Pq uint
Major number for zvol block devices.
.
-.It Sy zvol_max_discard_blocks Ns = Ns Sy 16384 Pq ulong
+.It Sy zvol_max_discard_blocks Ns = Ns Sy 16384 Pq long
Discard (TRIM) operations done on zvols will be done in batches of this
many blocks, where block size is determined by the
.Sy volblocksize
is ignored when running on a kernel that supports block multiqueue
.Pq Li blk-mq .
.
+.It Sy zvol_num_taskqs Ns = Ns Sy 0 Pq uint
+Number of zvol taskqs.
+If
+.Sy 0
+(the default) then scaling is done internally to prefer 6 threads per taskq.
+This only applies on Linux.
+.
.It Sy zvol_threads Ns = Ns Sy 0 Pq uint
The number of system wide threads to use for processing zvol block IOs.
If
.It Sy 3
.No equivalent to Sy none
.El
+.
+.It Sy zvol_enforce_quotas Ns = Ns Sy 0 Ns | Ns 1 Pq uint
+Enable strict ZVOL quota enforcement.
+The strict quota enforcement may have a performance impact.
.El
.
.Sh ZFS I/O SCHEDULER
Iteration through the I/O classes is done in the order specified above.
No further operations are issued
if the aggregate maximum number of concurrent operations has been hit,
-or if there are no operations queued for an I/O class that has not hit its maximum.
+or if there are no operations queued for an I/O class that has not hit its
+maximum.
Every time an I/O operation is queued or an operation completes,
the scheduler looks for new operations to issue.
.Pp
according to the amount of dirty data in the pool.
Since both throughput and latency typically increase with the number of
concurrent operations issued to physical devices, reducing the
-burstiness in the number of concurrent operations also stabilizes the
-response time of operations from other – and in particular synchronous – queues.
+burstiness in the number of simultaneous operations also stabilizes the
+response time of operations from other queues, in particular synchronous ones.
In broad strokes, the I/O scheduler will issue more concurrent operations
-from the async write queue as there's more dirty data in the pool.
+from the async write queue as there is more dirty data in the pool.
.
.Ss Async Writes
The number of concurrent operations issued for the async write I/O class
has failed to keep up with the incoming write rate.
The scale of the curve is defined by
.Sy zfs_delay_scale .
-Roughly speaking, this variable determines the amount of delay at the midpoint of the curve.
+Roughly speaking, this variable determines the amount of delay at the midpoint
+of the curve.
.Bd -literal
delay
10ms +-------------------------------------------------------------*+
projects / mirror_zfs.git / blobdiff