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 128MB Pc Pq int
+.It Sy dmu_prefetch_max Ns = Ns Sy 134217728 Ns B Po 128 MiB Pc Pq int
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.
.
.Sy 100
we TRIM twice the space required to accommodate upcoming writes.
A minimum of
-.Sy 64MB
+.Sy 64 MiB
will be trimmed.
It also enables TRIM of the whole L2ARC device upon creation
or addition to an existing pool or if the header of the device is
.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 8MB Pc Pq ulong
+.It Sy l2arc_write_boost Ns = Ns Sy 8388608 Ns B Po 8 MiB Pc Pq ulong
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 8MB Pc Pq ulong
+.It Sy l2arc_write_max Ns = Ns Sy 8388608 Ns B Po 8 MiB Pc Pq ulong
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 1GB Pc Pq ulong
+.It Sy l2arc_rebuild_blocks_min_l2size Ns = Ns Sy 1073741824 Ns B Po 1 GiB Pc Pq ulong
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
-For L2ARC devices less than 1GB, the amount of data
+For L2ARC devices less than 1 GiB, the amount of data
.Fn l2arc_evict
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 1MB Pc Pq ulong
+.It Sy metaslab_aliquot Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq ulong
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 Ns B Po 16MB + 1B Pc Pq ulong
+.It Sy metaslab_force_ganging Ns = Ns Sy 16777217 Ns B Po 16 MiB + 1 B Pc Pq ulong
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 Ns B Po 1MB Pc Pq int
+.It Sy zfs_history_output_max Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq int
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
-.Sy DMU_MAX_ACCESS Pq 64MB .
+.Sy DMU_MAX_ACCESS Pq 64 MiB .
This applies primarily to
.Fn zfs_ioc_channel_program Pq cf. Xr zfs-program 8 .
.
.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 16MB Pc Pq int
+.It Sy metaslab_df_max_search Ns = Ns Sy 16777216 Ns B Po 16 MiB Pc Pq int
Maximum distance to search forward from the last offset.
Without this limit, fragmented pools can see
.Em >100`000
becomes the performance limiting factor on high-performance storage.
.Pp
With the default setting of
-.Sy 16MB ,
+.Sy 16 MiB ,
we typically see less than
.Em 500
iterations, even with very fragmented
The maximum number of iterations possible is
.Sy metaslab_df_max_search / 2^(ashift+1) .
With the default setting of
-.Sy 16MB
+.Sy 16 MiB
this is
.Em 16*1024 Pq with Sy ashift Ns = Ns Sy 9
or
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 1h Pc Pq ulong
+.It Sy zfs_metaslab_max_size_cache_sec Ns = Ns Sy 3600 Ns s Po 1 hour Pc Pq ulong
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.
.It Sy zfs_vdev_default_ms_count Ns = Ns Sy 200 Pq int
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 512MB Pc Pq int
+.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_max_auto_ashift Ns = Ns Sy ASHIFT_MAX Po 16 Pc Pq ulong
.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 10min Pc Pq int
+.It Sy metaslab_unload_delay_ms Ns = Ns Sy 600000 Ns ms Po 10 min Pc Pq int
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
feature.
The default is to convert all log entries.
.
-.It Sy vdev_removal_max_span Ns = Ns Sy 32768 Ns B Po 32kB Pc Pq int
+.It Sy vdev_removal_max_span Ns = Ns Sy 32768 Ns B Po 32 KiB Pc Pq int
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 512B Pc Pq ulong
+.It Sy vdev_file_logical_ashift Ns = Ns Sy 9 Po 512 B Pc Pq ulong
Logical ashift for file-based devices.
.
-.It Sy vdev_file_physical_ashift Ns = Ns Sy 9 Po 512B Pc Pq ulong
+.It Sy vdev_file_physical_ashift Ns = Ns Sy 9 Po 512 B Pc Pq ulong
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 1MB Pc Pq ulong
+.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 zfetch_max_distance Ns = Ns Sy 8388608 Ns B Po 8MB Pc Pq uint
+.It Sy zfetch_max_distance Ns = Ns Sy 8388608 Ns B Po 8 MiB Pc Pq uint
Max bytes to prefetch per stream.
.
-.It Sy zfetch_max_idistance Ns = Ns Sy 67108864 Ns B Po 64MB Pc Pq uint
+.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_streams Ns = Ns Sy 8 Pq uint
.Sy MAX_ORDER
depends on kernel configuration.
.
-.It Sy zfs_abd_scatter_min_size Ns = Ns Sy 1536 Ns B Po 1.5kB Pc Pq uint
+.It Sy zfs_abd_scatter_min_size Ns = Ns Sy 1536 Ns B Po 1.5 KiB Pc Pq uint
This is the minimum allocation size that will use scatter (page-based) ABDs.
Smaller allocations will use linear ABDs.
.
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 8kB Pc Pq int
+.It Sy zfs_arc_average_blocksize Ns = Ns Sy 8192 Ns B Po 8 KiB Pc Pq int
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 1MB of hash table per 1GB of physical memory
+This works out to roughly 1 MiB of hash table per 1 GiB of physical memory
with 8-byte pointers.
For configurations with a known larger average block size,
this value can be increased to reduce the memory footprint.
.Fn arc_get_data_impl
waits for this percent of the requested amount of data to be evicted.
For example, by default, for every
-.Em 2kB
+.Em 2 KiB
that's evicted,
-.Em 1kB
+.Em 1 KiB
of it may be "reused" by a new allocation.
Since this is above
.Sy 100 Ns % ,
Under
.Fx ,
the larger of
-.Sy all_system_memory No \- Sy 1GB
+.Sy all_system_memory No \- Sy 1 GiB
and
.Sy 5/8 No \(mu Sy all_system_memory
will be used as the limit.
This value must be at least
-.Sy 67108864 Ns B Pq 64MB .
+.Sy 67108864 Ns B Pq 64 MiB .
.Pp
This value can be changed dynamically, with some caveats.
It cannot be set back to
Min size of ARC in bytes.
.No If set to Sy 0 , arc_c_min
will default to consuming the larger of
-.Sy 32MB
+.Sy 32 MiB
and
.Sy all_system_memory No / Sy 32 .
.
equivalent to a quarter of the user-wired memory limit under
.Fx
and to
-.Sy 134217728 Ns B Pq 128MB
+.Sy 134217728 Ns B Pq 128 MiB
under Linux.
.
.It Sy zfs_multilist_num_sublists Ns = Ns Sy 0 Pq int
up to about four times this for one allocation attempt.
.Pp
The default limit of
-.Sy 10000 Pq in practice, Em 160MB No per allocation attempt with 4kB pages
+.Sy 10000 Pq in practice, Em 160 MiB No per allocation attempt with 4 KiB pages
limits the amount of time spent attempting to reclaim ARC memory to
-less than 100ms per allocation attempt,
-even with a small average compressed block size of ~8kB.
+less than 100 ms per allocation attempt,
+even with a small average compressed block size of ~8 KiB.
.Pp
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
The target number of bytes the ARC should leave as free memory on the system.
If zero, equivalent to the bigger of
-.Sy 512kB No and Sy all_system_memory/64 .
+.Sy 512 KiB No and Sy all_system_memory/64 .
.
.It Sy zfs_autoimport_disable Ns = Ns Sy 1 Ns | Ns 0 Pq int
Disable pool import at module load by ignoring the cache file
bytes on-disk.
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 1GB Pc Pq ulong
+.It Sy zfs_condense_max_obsolete_bytes Ns = Ns Sy 1073741824 Ns B Po 1 GiB Pc Pq ulong
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 128kB Pc Pq ulong
+.It Sy zfs_condense_min_mapping_bytes Ns = Ns Sy 131072 Ns B Po 128 KiB Pc Pq ulong
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 4MB Pc Pq int
+.It Sy zfs_dbgmsg_maxsize Ns = Ns Sy 4194304 Ns B Po 4 MiB Pc Pq int
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 1min Pc Pq int
+.It Sy zfs_deadman_checktime_ms Ns = Ns Sy 60000 Ns ms Po 1 min Pc Pq int
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 10min Pc Pq ulong
+.It Sy zfs_deadman_synctime_ms Ns = Ns Sy 600000 Ns ms Po 10 min Pc Pq ulong
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 5min Pc Pq ulong
+.It Sy zfs_deadman_ziotime_ms Ns = Ns Sy 300000 Ns ms Po 5 min Pc Pq ulong
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",
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 1GB Pc Pq ulong
+.It Sy zfs_unflushed_max_mem_amt Ns = Ns Sy 1073741824 Ns B Po 1 GiB Pc Pq ulong
Upper-bound limit for unflushed metadata changes to be held by the
log spacemap in memory, in bytes.
.
can add up to no more than
.Sy 131072
blocks (which means
-.Em 16GB
+.Em 16 GiB
of logical space before compression and ditto blocks,
assuming that blocksize is
-.Em 128kB ) .
+.Em 128 KiB ) .
.Pp
This tunable is important because it involves a trade-off between import
time after an unclean export and the frequency of flushing metaslabs.
.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 32kB Pc Pq long
+.It Sy zfs_immediate_write_sz Ns = Ns Sy 32768 Ns B Po 32 KiB Pc Pq long
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
Pattern written to vdev free space by
.Xr zpool-initialize 8 .
.
-.It Sy zfs_initialize_chunk_size Ns = Ns Sy 1048576 Ns B Po 1MB Pc Pq ulong
+.It Sy zfs_initialize_chunk_size Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq ulong
Size of writes used by
.Xr zpool-initialize 8 .
This option is used by the test suite.
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 100MB Pc Pq ulong
+.It Sy zfs_lua_max_memlimit Ns = Ns Sy 104857600 Po 100 MiB Pc Pq ulong
The maximum memory limit that can be set for a ZFS channel program, specified
in bytes.
.
.It Sy zfs_max_logsm_summary_length Ns = Ns Sy 10 Pq ulong
Maximum number of rows allowed in the summary of the spacemap log.
.
-.It Sy zfs_max_recordsize Ns = Ns Sy 16777216 Po 16MB Pc Pq int
+.It Sy zfs_max_recordsize Ns = Ns Sy 16777216 Po 16 MiB Pc Pq int
We currently support block sizes from
-.Em 512B No to Em 16MB .
+.Em 512 Po 512 B Pc No to Em 16777216 Po 16 MiB Pc .
The benefits of larger blocks, and thus larger I/O,
need to be weighed against the cost of COWing a giant block to modify one byte.
Additionally, very large blocks can have an impact on I/O latency,
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 1s Pc Pq ulong
+.It Sy zfs_multihost_interval Ns = Ns Sy 1000 Ns ms Po 1 s Pc Pq ulong
Used to control the frequency of multihost writes which are performed when the
.Sy multihost
pool property is on.
at longer intervals than
.Sy zfs_multihost_interval .
A minimum of
-.Em 100ms
+.Em 100 ms
is enforced.
.Pp
.Sy 0 No is equivalent to Sy 1 .
flags are used allowing holes in a file to be accurately reported.
When disabled holes will not be reported in recently dirtied files.
.
-.It Sy zfs_pd_bytes_max Ns = Ns Sy 52428800 Ns B Po 50MB Pc Pq int
+.It Sy zfs_pd_bytes_max Ns = Ns Sy 52428800 Ns B Po 50 MiB Pc Pq int
The number of bytes which should be prefetched during a pool traversal, like
.Nm zfs Cm send
or other data crawling operations.
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 1MB Pc Pq long
+.It Sy zfs_vnops_read_chunk_size Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq long
Bytes to read per chunk.
.
.It Sy zfs_read_history Ns = Ns Sy 0 Pq int
.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 1MB Pc Pq ulong
+.It Sy zfs_rebuild_max_segment Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq ulong
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 32MB Pc Pq ulong
+.It Sy zfs_rebuild_vdev_limit Ns = Ns Sy 33554432 Ns B Po 32 MiB Pc Pq ulong
Maximum amount of I/O that can be concurrently issued for a sequential
resilver per leaf device, given in bytes.
.
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 16MB Pc Pq int
+.It Sy zfs_remove_max_segment Ns = Ns Sy 16777216 Ns B Po 16 MiB Pc Pq int
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 3s Pc Pq int
+.It Sy zfs_resilver_min_time_ms Ns = Ns Sy 3000 Ns ms Po 3 s Pc Pq int
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 1s Pc Pq int
+.It Sy zfs_scrub_min_time_ms Ns = Ns Sy 1000 Ns ms Po 1 s Pc Pq int
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 2h Pc Pq int
+.It Sy zfs_scan_checkpoint_intval Ns = Ns Sy 7200 Ns s Po 2 hour Pc Pq int
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.
where I/O is initiated as soon as it is discovered.
Unsetting will not affect scrubs or resilvers that are already in progress.
.
-.It Sy zfs_scan_max_ext_gap Ns = Ns Sy 2097152 Ns B Po 2MB Pc Pq int
+.It Sy zfs_scan_max_ext_gap Ns = Ns Sy 2097152 Ns B Po 2 MiB Pc Pq int
Sets the largest gap in bytes between scrub/resilver I/O operations
that will still be considered sequential for sorting purposes.
Changing this value will not
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 4MB Pc Pq int
+.It Sy zfs_scan_vdev_limit Ns = Ns Sy 4194304 Ns B Po 4 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.
.
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 1MB Pc Pq int
+.It Sy zfs_send_no_prefetch_queue_length Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq int
The maximum number of bytes allowed in
.Nm zfs Cm send Ns 's
internal queues.
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 16MB Pc Pq int
+.It Sy zfs_send_queue_length Ns = Ns Sy 16777216 Ns B Po 16 MiB Pc Pq int
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.
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 16MB Pc Pq int
+.It Sy zfs_recv_queue_length Ns = Ns Sy 16777216 Ns B Po 16 MiB Pc Pq int
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 1MB Pc Pq int
+.It Sy zfs_recv_write_batch_size Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq int
The maximum amount of data, in bytes, that
.Nm zfs Cm receive
will write in one DMU transaction.
This is the uncompressed size, even when receiving a compressed send stream.
This setting will not reduce the write size below a single block.
Capped at a maximum of
-.Sy 32MB .
+.Sy 32 MiB .
.
.It Sy zfs_override_estimate_recordsize Ns = Ns Sy 0 Ns | Ns 1 Pq ulong
Setting this variable overrides the default logic for estimating block
Flushing of data to disk is done in passes.
Defer frees starting in this pass.
.
-.It Sy zfs_spa_discard_memory_limit Ns = Ns Sy 16777216 Ns B Po 16MB Pc Pq int
+.It Sy zfs_spa_discard_memory_limit Ns = Ns Sy 16777216 Ns B Po 16 MiB Pc Pq int
Maximum memory used for prefetching a checkpoint's space map on each
vdev while discarding the checkpoint.
.
many blocks' size will change, and thus we have to re-allocate
(not overwrite) them.
It also increases the number of
-.Em 128kB
+.Em 128 KiB
allocations (e.g. for indirect blocks and spacemaps)
because these will not be compressed.
The
-.Em 128kB
+.Em 128 KiB
allocations are especially detrimental to performance
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.
.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 128MB Pc Pq uint
+.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.
.
-.It Sy zfs_trim_extent_bytes_min Ns = Ns Sy 32768 Ns B Po 32kB Pc Pq uint
+.It Sy zfs_trim_extent_bytes_min Ns = Ns Sy 32768 Ns B Po 32 KiB Pc Pq uint
Minimum size of TRIM commands.
TRIM ranges smaller than this will be skipped,
unless they're part of a larger range which was chunked.
will have been already been aggregated by the metaslab.
This option is provided for debugging and performance analysis.
.
-.It Sy zfs_vdev_aggregation_limit Ns = Ns Sy 1048576 Ns B Po 1MB Pc Pq int
+.It Sy zfs_vdev_aggregation_limit Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq int
Max vdev I/O aggregation size.
.
-.It Sy zfs_vdev_aggregation_limit_non_rotating Ns = Ns Sy 131072 Ns B Po 128kB Pc Pq int
+.It Sy zfs_vdev_aggregation_limit_non_rotating Ns = Ns Sy 131072 Ns B Po 128 KiB Pc Pq int
Max vdev I/O aggregation size for non-rotating media.
.
-.It Sy zfs_vdev_cache_bshift Ns = Ns Sy 16 Po 64kB Pc Pq int
+.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 16kB Pc Pq int
+.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 64kB .
+.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.
Operations within this that are not immediately following the previous operation
are incremented by half.
.
-.It Sy zfs_vdev_mirror_rotating_seek_offset Ns = Ns Sy 1048576 Ns B Po 1MB Pc Pq int
+.It Sy zfs_vdev_mirror_rotating_seek_offset Ns = Ns Sy 1048576 Ns B Po 1 MiB Pc Pq int
The maximum distance for the last queued I/O operation in which
the balancing algorithm considers an operation to have locality.
.No See Sx ZFS I/O SCHEDULER .
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 32kB Pc Pq int
+.It Sy zfs_vdev_read_gap_limit Ns = Ns Sy 32768 Ns B Po 32 KiB Pc Pq int
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 4kB Pc Pq int
+.It Sy zfs_vdev_write_gap_limit Ns = Ns Sy 4096 Ns B Po 4 KiB Pc Pq int
Aggregate write I/O operations if the on-disk gap between them is within this
threshold.
.
.Sy 0
disables duplicate detection.
.
-.It Sy zfs_zevent_retain_expire_secs Ns = Ns Sy 900 Ns s Po 15min Pc Pq int
+.It Sy zfs_zevent_retain_expire_secs Ns = Ns Sy 900 Ns s Po 15 min Pc Pq int
Lifespan for a recent ereport that was retained for duplicate checking.
.
.It Sy zfs_zil_clean_taskq_maxalloc Ns = Ns Sy 1048576 Pq int
.Sy 100%
will create a maximum of one thread per cpu.
.
-.It Sy zil_maxblocksize Ns = Ns Sy 131072 Ns B Po 128kB Pc Pq int
+.It Sy zil_maxblocksize Ns = Ns Sy 131072 Ns B Po 128 KiB Pc Pq int
This sets the maximum block size used by the ZIL.
On very fragmented pools, lowering this
-.Pq typically to Sy 36kB
+.Pq typically to Sy 36 KiB
can improve performance.
.
.It Sy zil_nocacheflush Ns = Ns Sy 0 Ns | Ns 1 Pq int
Disable intent logging replay.
Can be disabled for recovery from corrupted ZIL.
.
-.It Sy zil_slog_bulk Ns = Ns Sy 786432 Ns B Po 768kB Pc Pq ulong
+.It Sy zil_slog_bulk Ns = Ns Sy 786432 Ns B Po 768 KiB Pc Pq ulong
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.
or other locking primitive: typically conditions in which a thread in
the zio pipeline is looping indefinitely.
.
-.It Sy zio_slow_io_ms Ns = Ns Sy 30000 Ns ms Po 30s Pc Pq int
+.It Sy zio_slow_io_ms Ns = Ns Sy 30000 Ns ms Po 30 s Pc Pq int
When an I/O operation takes more than this much time to complete,
it's marked as slow.
Each slow operation causes a delay zevent.
.Sy volblocksize
property of a zvol.
.
-.It Sy zvol_prefetch_bytes Ns = Ns Sy 131072 Ns B Po 128kB Pc Pq uint
+.It Sy zvol_prefetch_bytes Ns = Ns Sy 131072 Ns B Po 128 KiB Pc Pq uint
When adding a zvol to the system, prefetch this many bytes
from the start and end of the volume.
Prefetching these regions of the volume is desirable,
Note, that since the delay is added to the outstanding time remaining on the
most recent transaction it's effectively the inverse of IOPS.
Here, the midpoint of
-.Em 500us
+.Em 500 us
translates to
.Em 2000 IOPS .
The shape of the curve
projects / mirror_zfs.git / commitdiff