Provided by: zfsutils-linux_2.3.1-1ubuntu2_amd64 
NAME
zpool-events — list recent events generated by kernel
SYNOPSIS
zpool events [-vHf] [pool]
zpool events -c
DESCRIPTION
Lists all recent events generated by the ZFS kernel modules. These events are consumed by the zed(8) and
used to automate administrative tasks such as replacing a failed device with a hot spare. For more
information about the subclasses and event payloads that can be generated see “EVENTS” and the following
sections.
OPTIONS
-c Clear all previous events.
-f Follow mode.
-H Scripted mode. Do not display headers, and separate fields by a single tab instead of arbitrary
space.
-v Print the entire payload for each event.
EVENTS
These are the different event subclasses. The full event name would be ereport.fs.zfs.SUBCLASS, but only
the last part is listed here.
checksum Issued when a checksum error has been detected.
io Issued when there is an I/O error in a vdev in the pool.
data Issued when there have been data errors in the pool.
deadman Issued when an I/O request is determined to be "hung", this can be caused by lost
completion events due to flaky hardware or drivers. See zfs_deadman_failmode in
zfs(4) for additional information regarding "hung" I/O detection and configuration.
delay Issued when a completed I/O request exceeds the maximum allowed time specified by the
zio_slow_io_ms module parameter. This can be an indicator of problems with the
underlying storage device. The number of delay events is ratelimited by the
zfs_slow_io_events_per_second module parameter.
dio_verify_rd Issued when there was a checksum verify error after a Direct I/O read has been issued.
dio_verify_wr Issued when there was a checksum verify error after a Direct I/O write has been
issued. This event can only take place if the module parameter
zfs_vdev_direct_write_verify is not set to zero. See zfs(4) for more details on the
zfs_vdev_direct_write_verify module paramter.
config Issued every time a vdev change have been done to the pool.
zpool Issued when a pool cannot be imported.
zpool.destroy Issued when a pool is destroyed.
zpool.export Issued when a pool is exported.
zpool.import Issued when a pool is imported.
zpool.reguid Issued when a REGUID (new unique identifier for the pool have been regenerated) have
been detected.
vdev.unknown Issued when the vdev is unknown. Such as trying to clear device errors on a vdev that
have failed/been kicked from the system/pool and is no longer available.
vdev.open_failed Issued when a vdev could not be opened (because it didn't exist for example).
vdev.corrupt_data Issued when corrupt data have been detected on a vdev.
vdev.no_replicas Issued when there are no more replicas to sustain the pool. This would lead to the
pool being DEGRADED.
vdev.bad_guid_sum Issued when a missing device in the pool have been detected.
vdev.too_small Issued when the system (kernel) have removed a device, and ZFS notices that the device
isn't there any more. This is usually followed by a probe_failure event.
vdev.bad_label Issued when the label is OK but invalid.
vdev.bad_ashift Issued when the ashift alignment requirement has increased.
vdev.remove Issued when a vdev is detached from a mirror (or a spare detached from a vdev where it
have been used to replace a failed drive - only works if the original drive have been
re-added).
vdev.clear Issued when clearing device errors in a pool. Such as running zpool clear on a device
in the pool.
vdev.check Issued when a check to see if a given vdev could be opened is started.
vdev.spare Issued when a spare have kicked in to replace a failed device.
vdev.autoexpand Issued when a vdev can be automatically expanded.
io_failure Issued when there is an I/O failure in a vdev in the pool.
probe_failure Issued when a probe fails on a vdev. This would occur if a vdev have been kicked from
the system outside of ZFS (such as the kernel have removed the device).
log_replay Issued when the intent log cannot be replayed. The can occur in the case of a missing
or damaged log device.
resilver.start Issued when a resilver is started.
resilver.finish Issued when the running resilver have finished.
scrub.start Issued when a scrub is started on a pool.
scrub.finish Issued when a pool has finished scrubbing.
scrub.abort Issued when a scrub is aborted on a pool.
scrub.resume Issued when a scrub is resumed on a pool.
scrub.paused Issued when a scrub is paused on a pool.
bootfs.vdev.attach
PAYLOADS
This is the payload (data, information) that accompanies an event.
For zed(8), these are set to uppercase and prefixed with ZEVENT_.
pool Pool name.
pool_failmode Failmode - wait, continue, or panic. See the failmode property in zpoolprops(7) for
more information.
pool_guid The GUID of the pool.
pool_context The load state for the pool (0=none, 1=open, 2=import, 3=tryimport, 4=recover
5=error).
vdev_guid The GUID of the vdev in question (the vdev failing or operated upon with zpool clear,
etc.).
vdev_type Type of vdev - disk, file, mirror, etc. See the Virtual Devices section of
zpoolconcepts(7) for more information on possible values.
vdev_path Full path of the vdev, including any -partX.
vdev_devid ID of vdev (if any).
vdev_fru Physical FRU location.
vdev_state State of vdev (0=uninitialized, 1=closed, 2=offline, 3=removed, 4=failed to open,
5=faulted, 6=degraded, 7=healthy).
vdev_ashift The ashift value of the vdev.
vdev_complete_ts The time the last I/O request completed for the specified vdev.
vdev_delta_ts The time since the last I/O request completed for the specified vdev.
vdev_spare_paths List of spares, including full path and any -partX.
vdev_spare_guids GUID(s) of spares.
vdev_read_errors How many read errors that have been detected on the vdev.
vdev_write_errors How many write errors that have been detected on the vdev.
vdev_cksum_errors How many checksum errors that have been detected on the vdev.
parent_guid GUID of the vdev parent.
parent_type Type of parent. See vdev_type.
parent_path Path of the vdev parent (if any).
parent_devid ID of the vdev parent (if any).
zio_objset The object set number for a given I/O request.
zio_object The object number for a given I/O request.
zio_level The indirect level for the block. Level 0 is the lowest level and includes data
blocks. Values > 0 indicate metadata blocks at the appropriate level.
zio_blkid The block ID for a given I/O request.
zio_err The error number for a failure when handling a given I/O request, compatible with
errno(3) with the value of EBADE used to indicate a ZFS checksum error.
zio_offset The offset in bytes of where to write the I/O request for the specified vdev.
zio_size The size in bytes of the I/O request.
zio_flags The current flags describing how the I/O request should be handled. See the I/O FLAGS
section for the full list of I/O flags.
zio_stage The current stage of the I/O in the pipeline. See the I/O STAGES section for a full
list of all the I/O stages.
zio_pipeline The valid pipeline stages for the I/O. See the I/O STAGES section for a full list of
all the I/O stages.
zio_delay The time elapsed (in nanoseconds) waiting for the block layer to complete the I/O
request. Unlike zio_delta, this does not include any vdev queuing time and is
therefore solely a measure of the block layer performance.
zio_timestamp The time when a given I/O request was submitted.
zio_delta The time required to service a given I/O request.
prev_state The previous state of the vdev.
cksum_algorithm Checksum algorithm used. See zfsprops(7) for more information on the available
checksum algorithms.
cksum_byteswap Whether or not the data is byteswapped.
bad_ranges [start, end) pairs of corruption offsets. Offsets are always aligned on a 64-bit
boundary, and can include some gaps of non-corruption. (See bad_ranges_min_gap)
bad_ranges_min_gap
In order to bound the size of the bad_ranges array, gaps of non-corruption less than
or equal to bad_ranges_min_gap bytes have been merged with adjacent corruption.
Always at least 8 bytes, since corruption is detected on a 64-bit word basis.
bad_range_sets This array has one element per range in bad_ranges. Each element contains the count
of bits in that range which were clear in the good data and set in the bad data.
bad_range_clears This array has one element per range in bad_ranges. Each element contains the count
of bits for that range which were set in the good data and clear in the bad data.
bad_set_bits If this field exists, it is an array of (bad data & ~(good data)); that is, the bits
set in the bad data which are cleared in the good data. Each element corresponds a
byte whose offset is in a range in bad_ranges, and the array is ordered by offset.
Thus, the first element is the first byte in the first bad_ranges range, and the last
element is the last byte in the last bad_ranges range.
bad_cleared_bits Like bad_set_bits, but contains (good data & ~(bad data)); that is, the bits set in
the good data which are cleared in the bad data.
I/O STAGES
The ZFS I/O pipeline is comprised of various stages which are defined below. The individual stages are
used to construct these basic I/O operations: Read, Write, Free, Claim, Flush and Trim. These stages may
be set on an event to describe the life cycle of a given I/O request.
Stage Bit Mask Operations
────────────────────────────────────────────────────────
ZIO_STAGE_OPEN 0x00000001 RWFCXT
ZIO_STAGE_READ_BP_INIT 0x00000002 R-----
ZIO_STAGE_WRITE_BP_INIT 0x00000004 -W----
ZIO_STAGE_FREE_BP_INIT 0x00000008 --F---
ZIO_STAGE_ISSUE_ASYNC 0x00000010 -WF--T
ZIO_STAGE_WRITE_COMPRESS 0x00000020 -W----
ZIO_STAGE_ENCRYPT 0x00000040 -W----
ZIO_STAGE_CHECKSUM_GENERATE 0x00000080 -W----
ZIO_STAGE_NOP_WRITE 0x00000100 -W----
ZIO_STAGE_BRT_FREE 0x00000200 --F---
ZIO_STAGE_DDT_READ_START 0x00000400 R-----
ZIO_STAGE_DDT_READ_DONE 0x00000800 R-----
ZIO_STAGE_DDT_WRITE 0x00001000 -W----
ZIO_STAGE_DDT_FREE 0x00002000 --F---
ZIO_STAGE_GANG_ASSEMBLE 0x00004000 RWFC--
ZIO_STAGE_GANG_ISSUE 0x00008000 RWFC--
ZIO_STAGE_DVA_THROTTLE 0x00010000 -W----
ZIO_STAGE_DVA_ALLOCATE 0x00020000 -W----
ZIO_STAGE_DVA_FREE 0x00040000 --F---
ZIO_STAGE_DVA_CLAIM 0x00080000 ---C--
ZIO_STAGE_READY 0x00100000 RWFCIT
ZIO_STAGE_VDEV_IO_START 0x00200000 RW--XT
ZIO_STAGE_VDEV_IO_DONE 0x00400000 RW--XT
ZIO_STAGE_VDEV_IO_ASSESS 0x00800000 RW--XT
ZIO_STAGE_CHECKSUM_VERIFY 0x01000000 R-----
ZIO_STAGE_DIO_CHECKSUM_VERIFY 0x02000000 -W----
ZIO_STAGE_DONE 0x04000000 RWFCXT
I/O FLAGS
Every I/O request in the pipeline contains a set of flags which describe its function and are used to
govern its behavior. These flags will be set in an event as a zio_flags payload entry.
Flag Bit Mask
─────────────────────────────────────
ZIO_FLAG_DONT_AGGREGATE 0x00000001
ZIO_FLAG_IO_REPAIR 0x00000002
ZIO_FLAG_SELF_HEAL 0x00000004
ZIO_FLAG_RESILVER 0x00000008
ZIO_FLAG_SCRUB 0x00000010
ZIO_FLAG_SCAN_THREAD 0x00000020
ZIO_FLAG_PHYSICAL 0x00000040
ZIO_FLAG_CANFAIL 0x00000080
ZIO_FLAG_SPECULATIVE 0x00000100
ZIO_FLAG_CONFIG_WRITER 0x00000200
ZIO_FLAG_DONT_RETRY 0x00000400
ZIO_FLAG_NODATA 0x00001000
ZIO_FLAG_INDUCE_DAMAGE 0x00002000
ZIO_FLAG_IO_ALLOCATING 0x00004000
ZIO_FLAG_IO_RETRY 0x00008000
ZIO_FLAG_PROBE 0x00010000
ZIO_FLAG_TRYHARD 0x00020000
ZIO_FLAG_OPTIONAL 0x00040000
ZIO_FLAG_DONT_QUEUE 0x00080000
ZIO_FLAG_DONT_PROPAGATE 0x00100000
ZIO_FLAG_IO_BYPASS 0x00200000
ZIO_FLAG_IO_REWRITE 0x00400000
ZIO_FLAG_RAW_COMPRESS 0x00800000
ZIO_FLAG_RAW_ENCRYPT 0x01000000
ZIO_FLAG_GANG_CHILD 0x02000000
ZIO_FLAG_DDT_CHILD 0x04000000
ZIO_FLAG_GODFATHER 0x08000000
ZIO_FLAG_NOPWRITE 0x10000000
ZIO_FLAG_REEXECUTED 0x20000000
ZIO_FLAG_DELEGATED 0x40000000
ZIO_FLAG_FASTWRITE 0x80000000
SEE ALSO
zfs(4), zed(8), zpool-wait(8)
OpenZFS February 28, 2024 ZPOOL-EVENTS(8)