'\" te
.\" Copyright (c) 2013 by Turbo Fredriksson <turbo@bayour.com>. All rights reserved.
.\" Copyright (c) 2017 Datto Inc.
+.\" Copyright (c) 2018 by Delphix. All rights reserved.
.\" 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
.sp
.LP
+.sp
+.ne 2
+.na
+\fBdbuf_cache_max_bytes\fR (ulong)
+.ad
+.RS 12n
+Maximum size in bytes of the dbuf cache. When \fB0\fR this value will default
+to \fB1/2^dbuf_cache_shift\fR (1/32) of the target ARC size, otherwise the
+provided value in bytes will be used. The behavior of the dbuf cache and its
+associated settings can be observed via the \fB/proc/spl/kstat/zfs/dbufstats\fR
+kstat.
+.sp
+Default value: \fB0\fR.
+.RE
+
+.sp
+.ne 2
+.na
+\fBdbuf_metadata_cache_max_bytes\fR (ulong)
+.ad
+.RS 12n
+Maximum size in bytes of the metadata dbuf cache. When \fB0\fR this value will
+default to \fB1/2^dbuf_cache_shift\fR (1/16) of the target ARC size, otherwise
+the provided value in bytes will be used. The behavior of the metadata dbuf
+cache and its associated settings can be observed via the
+\fB/proc/spl/kstat/zfs/dbufstats\fR kstat.
+.sp
+Default value: \fB0\fR.
+.RE
+
+.sp
+.ne 2
+.na
+\fBdbuf_cache_hiwater_pct\fR (uint)
+.ad
+.RS 12n
+The percentage over \fBdbuf_cache_max_bytes\fR when dbufs must be evicted
+directly.
+.sp
+Default value: \fB10\fR%.
+.RE
+
+.sp
+.ne 2
+.na
+\fBdbuf_cache_lowater_pct\fR (uint)
+.ad
+.RS 12n
+The percentage below \fBdbuf_cache_max_bytes\fR when the evict thread stops
+evicting dbufs.
+.sp
+Default value: \fB10\fR%.
+.RE
+
+.sp
+.ne 2
+.na
+\fBdbuf_cache_shift\fR (int)
+.ad
+.RS 12n
+Set the size of the dbuf cache, \fBdbuf_cache_max_bytes\fR, to a log2 fraction
+of the target arc size.
+.sp
+Default value: \fB5\fR.
+.RE
+
+.sp
+.ne 2
+.na
+\fBdbuf_metadata_cache_shift\fR (int)
+.ad
+.RS 12n
+Set the size of the dbuf metadata cache, \fBdbuf_metadata_cache_max_bytes\fR,
+to a log2 fraction of the target arc size.
+.sp
+Default value: \fB6\fR.
+.RE
+
.sp
.ne 2
.na
Scales \fBl2arc_headroom\fR by this percentage when L2ARC contents are being
successfully compressed before writing. A value of 100 disables this feature.
.sp
-Default value: \fB200\fR.
-.RE
-
-.sp
-.ne 2
-.na
-\fBl2arc_nocompress\fR (int)
-.ad
-.RS 12n
-Skip compressing L2ARC buffers
-.sp
-Use \fB1\fR for yes and \fB0\fR for no (default).
+Default value: \fB200\fR%.
.RE
.sp
Use \fB1\fR for yes (default) and \fB0\fR for no.
.RE
+.sp
+.ne 2
+.na
+\fBmetaslab_force_ganging\fR (ulong)
+.ad
+.RS 12n
+Make some blocks above a certain size be gang blocks. This option is used
+by the test suite to facilitate testing.
+.sp
+Default value: \fB16,777,217\fR.
+.RE
+
.sp
.ne 2
.na
.sp
.ne 2
.na
-\fBmetaslabs_per_vdev\fR (int)
+\fBvdev_max_ms_count\fR (int)
.ad
.RS 12n
-When a vdev is added, it will be divided into approximately (but no more than) this number of metaslabs.
+When a vdev is added target this number of metaslabs per top-level vdev.
.sp
Default value: \fB200\fR.
.RE
+.sp
+.ne 2
+.na
+\fBvdev_min_ms_count\fR (int)
+.ad
+.RS 12n
+Minimum number of metaslabs to create in a top-level vdev.
+.sp
+Default value: \fB16\fR.
+.RE
+
+.sp
+.ne 2
+.na
+\fBvdev_ms_count_limit\fR (int)
+.ad
+.RS 12n
+Practical upper limit of total metaslabs per top-level vdev.
+.sp
+Default value: \fB131,072\fR.
+.RE
+
.sp
.ne 2
.na
Default value: \fB24\fR.
.RE
+.sp
+.ne 2
+.na
+\fBspa_load_print_vdev_tree\fR (int)
+.ad
+.RS 12n
+Whether to print the vdev tree in the debugging message buffer during pool import.
+Use 0 to disable and 1 to enable.
+.sp
+Default value: \fB0\fR.
+.RE
+
.sp
.ne 2
.na
Default value: \fB5\fR.
.RE
+.sp
+.ne 2
+.na
+\fBvdev_removal_max_span\fR (int)
+.ad
+.RS 12n
+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 will be included as "unnecessary" data in a chunk of copied data.
+
+The default value here was chosen to align with
+\fBzfs_vdev_read_gap_limit\fR, which is a similar concept when doing
+regular reads (but there's no reason it has to be the same).
+.sp
+Default value: \fB32,768\fR.
+.RE
+
.sp
.ne 2
.na
See also \fBzfs_arc_dnode_limit\fR which serves a similar purpose but has a
higher priority if set to nonzero value.
.sp
-Default value: \fB10\fR.
+Default value: \fB10\fR%.
.RE
.sp
when the number of bytes consumed by dnodes exceeds \fBzfs_arc_dnode_limit\fR.
.sp
-Default value: \fB10% of the number of dnodes in the ARC\fR.
+Default value: \fB10\fR% of the number of dnodes in the ARC.
.RE
.sp
Throttle I/O when free system memory drops below this percentage of total
system memory. Setting this value to 0 will disable the throttle.
.sp
-Default value: \fB10\fR.
+Default value: \fB10\fR%.
.RE
.sp
higher priority if set to nonzero value.
.sp
-Default value: \fB75\fR.
+Default value: \fB75\fR%.
.RE
.sp
.ad
.RS 12n
Minimum time prefetched blocks are locked in the ARC, specified in ms.
-A value of \fB0\fR will default to 1 second.
+A value of \fB0\fR will default to 1000 ms.
.sp
Default value: \fB0\fR.
.RE
.RS 12n
Minimum time "prescient prefetched" blocks are locked in the ARC, specified
in ms. These blocks are meant to be prefetched fairly aggresively ahead of
-the code that may use them. A value of \fB0\fR will default to 6 seconds.
+the code that may use them. A value of \fB0\fR will default to 6000 ms.
.sp
Default value: \fB0\fR.
.RE
+.sp
+.ne 2
+.na
+\fBzfs_max_missing_tvds\fR (int)
+.ad
+.RS 12n
+Number of missing top-level vdevs which will be allowed during
+pool import (only in read-only mode).
+.sp
+Default value: \fB0\fR
+.RE
+
.sp
.ne 2
.na
Default value: \fB0\fR.
.RE
-.sp
-.ne 2
-.na
-\fBzfs_arc_p_aggressive_disable\fR (int)
-.ad
-.RS 12n
-Disable aggressive arc_p growth
-.sp
-Use \fB1\fR for yes (default) and \fB0\fR to disable.
-.RE
-
.sp
.ne 2
.na
size (as measured by NR_FILE_PAGES) where that percent may exceed 100. This
only operates during memory pressure/reclaim.
.sp
-Default value: \fB0\fR (disabled).
+Default value: \fB0\fR% (disabled).
.RE
.sp
Use \fB1\fR for yes (default) and \fB0\fR for no.
.RE
+.sp
+.ne 2
+.na
+\fBzfs_checksums_per_second\fR (int)
+.ad
+.RS 12n
+Rate limit checksum events to this many per second. Note that this should
+not be set below the zed thresholds (currently 10 checksums over 10 sec)
+or else zed may not trigger any action.
+.sp
+Default value: 20
+.RE
+
.sp
.ne 2
.na
latency to avoid significantly impacting the latency of each individual
transaction record (itx).
.sp
-Default value: \fB5\fR.
+Default value: \fB5\fR%.
+.RE
+
+.sp
+.ne 2
+.na
+\fBzfs_condense_indirect_vdevs_enable\fR (int)
+.ad
+.RS 12n
+Enable condensing indirect vdev mappings. When set to a non-zero value,
+attempt to condense indirect vdev mappings if the mapping uses more than
+\fBzfs_condense_min_mapping_bytes\fR bytes of memory and if the obsolete
+space map object uses more than \fBzfs_condense_max_obsolete_bytes\fR
+bytes on-disk. The condensing process is an attempt to save memory by
+removing obsolete mappings.
+.sp
+Default value: \fB1\fR.
+.RE
+
+.sp
+.ne 2
+.na
+\fBzfs_condense_max_obsolete_bytes\fR (ulong)
+.ad
+.RS 12n
+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
+(see \fBfBzfs_condense_indirect_vdevs_enable\fR).
+.sp
+Default value: \fB1,073,741,824\fR.
+.RE
+
+.sp
+.ne 2
+.na
+\fBzfs_condense_min_mapping_bytes\fR (ulong)
+.ad
+.RS 12n
+Minimum size vdev mapping to attempt to condense (see
+\fBzfs_condense_indirect_vdevs_enable\fR).
+.sp
+Default value: \fB131,072\fR.
.RE
.sp
.ad
.RS 12n
When a pool sync operation takes longer than \fBzfs_deadman_synctime_ms\fR
-milliseconds, a "slow spa_sync" message is logged to the debug log
-(see \fBzfs_dbgmsg_enable\fR). If \fBzfs_deadman_enabled\fR is set,
-all pending IO operations are also checked and if any haven't completed
-within \fBzfs_deadman_synctime_ms\fR milliseconds, a "SLOW IO" message
-is logged to the debug log and a "delay" system event with the details of
-the hung IO is posted.
+milliseconds, or when an individual I/O takes longer than
+\fBzfs_deadman_ziotime_ms\fR milliseconds, then the operation is considered to
+be "hung". If \fBzfs_deadman_enabled\fR is set then the deadman behavior is
+invoked as described by the \fBzfs_deadman_failmode\fR module option.
+By default the deadman is enabled and configured to \fBwait\fR which results
+in "hung" I/Os only being logged. The deadman is automatically disabled
+when a pool gets suspended.
+.sp
+Default value: \fB1\fR.
+.RE
+
+.sp
+.ne 2
+.na
+\fBzfs_deadman_failmode\fR (charp)
+.ad
+.RS 12n
+Controls the failure behavior when the deadman detects a "hung" I/O. Valid
+values are \fBwait\fR, \fBcontinue\fR, and \fBpanic\fR.
+.sp
+\fBwait\fR - Wait for a "hung" I/O to complete. For each "hung" I/O a
+"deadman" event will be posted describing that I/O.
+.sp
+\fBcontinue\fR - Attempt to recover from a "hung" I/O by re-dispatching it
+to the I/O pipeline if possible.
.sp
-Use \fB1\fR (default) to enable the slow IO check and \fB0\fR to disable.
+\fBpanic\fR - Panic the system. This can be used to facilitate an automatic
+fail-over to a properly configured fail-over partner.
+.sp
+Default value: \fBwait\fR.
.RE
.sp
\fBzfs_deadman_checktime_ms\fR (int)
.ad
.RS 12n
-Once a pool sync operation has taken longer than
-\fBzfs_deadman_synctime_ms\fR milliseconds, continue to check for slow
-operations every \fBzfs_deadman_checktime_ms\fR milliseconds.
+Check time in milliseconds. This defines the frequency at which we check
+for hung I/O and potentially invoke the \fBzfs_deadman_failmode\fR behavior.
.sp
-Default value: \fB5,000\fR.
+Default value: \fB60,000\fR.
.RE
.sp
.ad
.RS 12n
Interval in milliseconds after which the deadman is triggered and also
-the interval after which an IO operation is considered to be "hung"
-if \fBzfs_deadman_enabled\fR is set.
+the interval after which a pool sync operation is considered to be "hung".
+Once this limit is exceeded the deadman will be invoked every
+\fBzfs_deadman_checktime_ms\fR milliseconds until the pool sync completes.
+.sp
+Default value: \fB600,000\fR.
+.RE
-See \fBzfs_deadman_enabled\fR.
.sp
-Default value: \fB1,000,000\fR.
+.ne 2
+.na
+\fBzfs_deadman_ziotime_ms\fR (ulong)
+.ad
+.RS 12n
+Interval in milliseconds after which the deadman is triggered and an
+individual IO operation is considered to be "hung". As long as the I/O
+remains "hung" the deadman will be invoked every \fBzfs_deadman_checktime_ms\fR
+milliseconds until the I/O completes.
+.sp
+Default value: \fB300,000\fR.
.RE
.sp
This value should be >= zfs_vdev_async_write_active_max_dirty_percent.
See the section "ZFS TRANSACTION DELAY".
.sp
-Default value: \fB60\fR.
+Default value: \fB60\fR%.
.RE
.sp
Default value: \fB500,000\fR.
.RE
+.sp
+.ne 2
+.na
+\fBzfs_delays_per_second\fR (int)
+.ad
+.RS 12n
+Rate limit IO delay events to this many per second.
+.sp
+Default value: 20
+.RE
+
.sp
.ne 2
.na
over \fBzfs_dirty_data_max_percent\fR.
See the section "ZFS TRANSACTION DELAY".
.sp
-Default value: 10 percent of all memory, capped at \fBzfs_dirty_data_max_max\fR.
+Default value: \fB10\fR% of physical RAM, capped at \fBzfs_dirty_data_max_max\fR.
.RE
.sp
precedence over \fBzfs_dirty_data_max_max_percent\fR. See the section
"ZFS TRANSACTION DELAY".
.sp
-Default value: 25% of physical RAM.
+Default value: \fB25\fR% of physical RAM.
.RE
.sp
The parameter \fBzfs_dirty_data_max_max\fR takes precedence over this
one. See the section "ZFS TRANSACTION DELAY".
.sp
-Default value: \fB25\fR.
+Default value: \fB25\fR%.
.RE
.sp
up. The parameter \fBzfs_dirty_data_max\fR takes precedence over this
one. See the section "ZFS TRANSACTION DELAY".
.sp
-Default value: 10%, subject to \fBzfs_dirty_data_max_max\fR.
+Default value: \fB10\fR%, subject to \fBzfs_dirty_data_max_max\fR.
.RE
.sp
.sp
.ne 2
.na
-\fBzfs_free_max_blocks\fR (ulong)
+\fBzfs_async_block_max_blocks\fR (ulong)
.ad
.RS 12n
Maximum number of blocks freed in a single txg.
Default value: \fB100,000\fR.
.RE
+.sp
+.ne 2
+.na
+\fBzfs_override_estimate_recordsize\fR (ulong)
+.ad
+.RS 12n
+Record size calculation override for zfs send estimates.
+.sp
+Default value: \fB0\fR.
+.RE
+
.sp
.ne 2
.na
the dirty data is between min and max, the active I/O limit is linearly
interpolated. See the section "ZFS I/O SCHEDULER".
.sp
-Default value: \fB60\fR.
+Default value: \fB60\fR%.
.RE
.sp
the dirty data is between min and max, the active I/O limit is linearly
interpolated. See the section "ZFS I/O SCHEDULER".
.sp
-Default value: \fB30\fR.
+Default value: \fB30\fR%.
.RE
.sp
See also \fBzio_dva_throttle_enabled\fR.
.sp
-Default value: \fB1000\fR.
-.RE
-
-.sp
-.ne 2
-.na
-\fBzfs_disable_dup_eviction\fR (int)
-.ad
-.RS 12n
-Disable duplicate buffer eviction
-.sp
-Use \fB1\fR for yes and \fB0\fR for no (default).
+Default value: \fB1000\fR%.
.RE
.sp
16 ZFS_DEBUG_MODIFY
Check for illegally modified ARC buffers.
_
-32 ZFS_DEBUG_SPA
- Enable spa_dbgmsg entries in the debug log.
-_
64 ZFS_DEBUG_ZIO_FREE
Enable verification of block frees.
_
Default value: \fB32,768\fR.
.RE
+.sp
+.ne 2
+.na
+\fBzfs_lua_max_instrlimit\fR (ulong)
+.ad
+.RS 12n
+The maximum execution time limit that can be set for a ZFS channel program,
+specified as a number of Lua instructions.
+.sp
+Default value: \fB100,000,000\fR.
+.RE
+
+.sp
+.ne 2
+.na
+\fBzfs_lua_max_memlimit\fR (ulong)
+.ad
+.RS 12n
+The maximum memory limit that can be set for a ZFS channel program, specified
+in bytes.
+.sp
+Default value: \fB104,857,600\fR.
+.RE
+
+.sp
+.ne 2
+.na
+\fBzfs_max_dataset_nesting\fR (int)
+.ad
+.RS 12n
+The maximum depth of nested datasets. This value can be tuned temporarily to
+fix existing datasets that exceed the predefined limit.
+.sp
+Default value: \fB50\fR.
+.RE
+
.sp
.ne 2
.na
Default value: \fB1,048,576\fR.
.RE
-.sp
-.ne 2
-.na
-\fBzfs_mdcomp_disable\fR (int)
-.ad
-.RS 12n
-Disable meta data compression
-.sp
-Use \fB1\fR for yes and \fB0\fR for no (default).
-.RE
-
.sp
.ne 2
.na
Default value: \fB0\fR.
.RE
+.sp
+.ne 2
+.na
+\fBzfs_ddt_data_is_special\fR (int)
+.ad
+.RS 12n
+If enabled, ZFS will place DDT data into the special allocation class.
+.sp
+Default value: \fB1\fR.
+.RE
+
+.sp
+.ne 2
+.na
+\fBzfs_user_indirect_is_special\fR (int)
+.ad
+.RS 12n
+If enabled, ZFS will place user data (both file and zvol) indirect blocks
+into the special allocation class.
+.sp
+Default value: \fB1\fR.
+.RE
+
.sp
.ne 2
.na
Use \fB1\fR for yes and \fB0\fR for no (default).
.RE
+.sp
+.ne 2
+.na
+\fBzfs_reconstruct_indirect_combinations_max\fR (int)
+.ad
+.RS 12na
+If an indirect split block contains more than this many possible unique
+combinations when being reconstructed, consider it too computationally
+expensive to check them all. Instead, try at most
+\fBzfs_reconstruct_indirect_combinations_max\fR randomly-selected
+combinations each time the block is accessed. This allows all segment
+copies to participate fairly in the reconstruction when all combinations
+cannot be checked and prevents repeated use of one bad copy.
+.sp
+Default value: \fB100\fR.
+.RE
+
.sp
.ne 2
.na
Default value: \fB3,000\fR.
.RE
+.sp
+.ne 2
+.na
+\fBzfs_scan_ignore_errors\fR (int)
+.ad
+.RS 12n
+If set to a nonzero value, remove the DTL (dirty time list) upon
+completion of a pool scan (scrub) even if there were unrepairable
+errors. It is intended to be used during pool repair or recovery to
+stop resilvering when the pool is next imported.
+.sp
+Default value: \fB0\fR.
+.RE
+
.sp
.ne 2
.na
To preserve progress across reboots the sequential scan algorithm periodically
needs to stop metadata scanning and issue all the verifications I/Os to disk.
The frequency of this flushing is determined by the
-\fBfBzfs_scan_checkpoint_intval\fR tunable.
+\fBzfs_scan_checkpoint_intval\fR tunable.
.sp
Default value: \fB7200\fR seconds (every 2 hours).
.RE
Use \fB1\fR for yes and \fB0\fR for no (default).
.RE
+.sp
+.ne 2
+.na
+\fBzfs_send_queue_length\fR (int)
+.ad
+.RS 12n
+The maximum number of bytes allowed in the \fBzfs send\fR queue. This value
+must be at least twice the maximum block size in use.
+.sp
+Default value: \fB16,777,216\fR.
+.RE
+
+.sp
+.ne 2
+.na
+\fBzfs_recv_queue_length\fR (int)
+.ad
+.RS 12n
+.sp
+The maximum number of bytes allowed in the \fBzfs receive\fR queue. This value
+must be at least twice the maximum block size in use.
+.sp
+Default value: \fB16,777,216\fR.
+.RE
+
.sp
.ne 2
.na
Default value: \fB2\fR.
.RE
+.sp
+.ne 2
+.na
+\fBzfs_spa_discard_memory_limit\fR (int)
+.ad
+.RS 12n
+Maximum memory used for prefetching a checkpoint's space map on each
+vdev while discarding the checkpoint.
+.sp
+Default value: \fB16,777,216\fR.
+.RE
+
.sp
.ne 2
.na
This controls the number of threads used by the dp_sync_taskq. The default
value of 75% will create a maximum of one thread per cpu.
.sp
-Default value: \fB75\fR.
+Default value: \fB75\fR%.
.RE
.sp
This controls the number of threads used by the dp_zil_clean_taskq. The default
value of 100% will create a maximum of one thread per cpu.
.sp
-Default value: \fB100\fR.
+Default value: \fB100\fR%.
.RE
.sp
Default value: \fB786,432\fR.
.RE
+.sp
+.ne 2
+.na
+\fBzio_decompress_fail_fraction\fR (int)
+.ad
+.RS 12n
+If non-zero, this value represents the denominator of the probability that zfs
+should induce a decompression failure. For instance, for a 5% decompression
+failure rate, this value should be set to 20.
+.sp
+Default value: \fB0\fR.
+.RE
+
.sp
.ne 2
.na
\fBzfs_qat_disable\fR (int)
.ad
.RS 12n
-This tunable disables qat hardware acceleration for gzip compression.
-It is available only if qat acceleration is compiled in and qat driver
-is present.
+This tunable disables qat hardware acceleration for gzip compression and.
+AES-GCM encryption. It is available only if qat acceleration is compiled in
+and the qat driver is present.
.sp
Use \fB1\fR for yes and \fB0\fR for no (default).
.RE
projects / mirror_zfs.git / blobdiff