zfs/man/man8/zpool-events.8

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.\" Copyright (c) 2012 Cyril Plisko. All Rights Reserved.
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.Dd May 27, 2021
.Dt ZPOOL-EVENTS 8
.Os
.
.Sh NAME
.Nm zpool-events
.Nd list recent events generated by kernel
.Sh SYNOPSIS
.Nm zpool
.Cm events
.Op Fl vHf
.Op Ar pool
.Nm zpool
.Cm events
.Fl c
.
.Sh DESCRIPTION
Lists all recent events generated by the ZFS kernel modules.
These events are consumed by the
.Xr 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
.Sx EVENTS
and the following sections.
.
.Sh OPTIONS
.Bl -tag -compact -width Ds
.It Fl c
Clear all previous events.
.It Fl f
Follow mode.
.It Fl H
Scripted mode.
Do not display headers, and separate fields by a
single tab instead of arbitrary space.
.It Fl v
Print the entire payload for each event.
.El
.
.Sh EVENTS
These are the different event subclasses.
The full event name would be
.Sy ereport.fs.zfs.\& Ns Em SUBCLASS ,
but only the last part is listed here.
.Pp
.Bl -tag -compact -width "vdev.bad_guid_sum"
.It Sy checksum
Issued when a checksum error has been detected.
.It Sy io
Issued when there is an I/O error in a vdev in the pool.
.It Sy data
Issued when there have been data errors in the pool.
.It Sy 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
.Sy zfs_deadman_failmode
in
.Xr zfs 4
for additional information regarding "hung" I/O detection and configuration.
.It Sy delay
Issued when a completed I/O request exceeds the maximum allowed time
specified by the
.Sy 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
.Sy zfs_slow_io_events_per_second
module parameter.
.It Sy config
Issued every time a vdev change have been done to the pool.
.It Sy zpool
Issued when a pool cannot be imported.
.It Sy zpool.destroy
Issued when a pool is destroyed.
.It Sy zpool.export
Issued when a pool is exported.
.It Sy zpool.import
Issued when a pool is imported.
.It Sy zpool.reguid
Issued when a REGUID (new unique identifier for the pool have been regenerated)
have been detected.
.It Sy 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.
.It Sy vdev.open_failed
Issued when a vdev could not be opened (because it didn't exist for example).
.It Sy vdev.corrupt_data
Issued when corrupt data have been detected on a vdev.
.It Sy vdev.no_replicas
Issued when there are no more replicas to sustain the pool.
This would lead to the pool being
.Em DEGRADED .
.It Sy vdev.bad_guid_sum
Issued when a missing device in the pool have been detected.
.It Sy 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
.Sy probe_failure
event.
.It Sy vdev.bad_label
Issued when the label is OK but invalid.
.It Sy vdev.bad_ashift
Issued when the ashift alignment requirement has increased.
.It Sy 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).
.It Sy vdev.clear
Issued when clearing device errors in a pool.
Such as running
.Nm zpool Cm clear
on a device in the pool.
.It Sy vdev.check
Issued when a check to see if a given vdev could be opened is started.
.It Sy vdev.spare
Issued when a spare have kicked in to replace a failed device.
.It Sy vdev.autoexpand
Issued when a vdev can be automatically expanded.
.It Sy io_failure
Issued when there is an I/O failure in a vdev in the pool.
.It Sy 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).
.It Sy log_replay
Issued when the intent log cannot be replayed.
The can occur in the case of a missing or damaged log device.
.It Sy resilver.start
Issued when a resilver is started.
.It Sy resilver.finish
Issued when the running resilver have finished.
.It Sy scrub.start
Issued when a scrub is started on a pool.
.It Sy scrub.finish
Issued when a pool has finished scrubbing.
.It Sy scrub.abort
Issued when a scrub is aborted on a pool.
.It Sy scrub.resume
Issued when a scrub is resumed on a pool.
.It Sy scrub.paused
Issued when a scrub is paused on a pool.
.It Sy bootfs.vdev.attach
.El
.
.Sh PAYLOADS
This is the payload (data, information) that accompanies an
event.
.Pp
For
.Xr zed 8 ,
these are set to uppercase and prefixed with
.Sy ZEVENT_ .
.Pp
.Bl -tag -compact -width "vdev_cksum_errors"
.It Sy pool
Pool name.
.It Sy pool_failmode
Failmode -
.Sy wait ,
.Sy continue ,
or
.Sy panic .
See the
.Sy failmode
property in
.Xr zpoolprops 7
for more information.
.It Sy pool_guid
The GUID of the pool.
.It Sy pool_context
The load state for the pool (0=none, 1=open, 2=import, 3=tryimport, 4=recover
5=error).
.It Sy vdev_guid
The GUID of the vdev in question (the vdev failing or operated upon with
.Nm zpool Cm clear ,
etc.).
.It Sy vdev_type
Type of vdev -
.Sy disk ,
.Sy file ,
.Sy mirror ,
etc.
See the
.Sy Virtual Devices
section of
.Xr zpoolconcepts 7
for more information on possible values.
.It Sy vdev_path
Full path of the vdev, including any
.Em -partX .
.It Sy vdev_devid
ID of vdev (if any).
.It Sy vdev_fru
Physical FRU location.
.It Sy vdev_state
State of vdev (0=uninitialized, 1=closed, 2=offline, 3=removed, 4=failed to
open, 5=faulted, 6=degraded, 7=healthy).
.It Sy vdev_ashift
The ashift value of the vdev.
.It Sy vdev_complete_ts
The time the last I/O request completed for the specified vdev.
.It Sy vdev_delta_ts
The time since the last I/O request completed for the specified vdev.
.It Sy vdev_spare_paths
List of spares, including full path and any
.Em -partX .
.It Sy vdev_spare_guids
GUID(s) of spares.
.It Sy vdev_read_errors
How many read errors that have been detected on the vdev.
.It Sy vdev_write_errors
How many write errors that have been detected on the vdev.
.It Sy vdev_cksum_errors
How many checksum errors that have been detected on the vdev.
.It Sy parent_guid
GUID of the vdev parent.
.It Sy parent_type
Type of parent.
See
.Sy vdev_type .
.It Sy parent_path
Path of the vdev parent (if any).
.It Sy parent_devid
ID of the vdev parent (if any).
.It Sy zio_objset
The object set number for a given I/O request.
.It Sy zio_object
The object number for a given I/O request.
.It Sy 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.
.It Sy zio_blkid
The block ID for a given I/O request.
.It Sy zio_err
The error number for a failure when handling a given I/O request,
compatible with
.Xr errno 3
with the value of
.Sy EBADE
used to indicate a ZFS checksum error.
.It Sy zio_offset
The offset in bytes of where to write the I/O request for the specified vdev.
.It Sy zio_size
The size in bytes of the I/O request.
.It Sy zio_flags
The current flags describing how the I/O request should be handled.
See the
.Sy I/O FLAGS
section for the full list of I/O flags.
.It Sy zio_stage
The current stage of the I/O in the pipeline.
See the
.Sy I/O STAGES
section for a full list of all the I/O stages.
.It Sy zio_pipeline
The valid pipeline stages for the I/O.
See the
.Sy I/O STAGES
section for a full list of all the I/O stages.
.It Sy zio_delay
The time elapsed (in nanoseconds) waiting for the block layer to complete the
I/O request.
Unlike
.Sy zio_delta ,
this does not include any vdev queuing time and is
therefore solely a measure of the block layer performance.
.It Sy zio_timestamp
The time when a given I/O request was submitted.
.It Sy zio_delta
The time required to service a given I/O request.
.It Sy prev_state
The previous state of the vdev.
.It Sy cksum_expected
The expected checksum value for the block.
.It Sy cksum_actual
The actual checksum value for an errant block.
.It Sy cksum_algorithm
Checksum algorithm used.
See
.Xr zfsprops 7
for more information on the available checksum algorithms.
.It Sy cksum_byteswap
Whether or not the data is byteswapped.
.It Sy bad_ranges
.No [\& Ns Ar start , end )
pairs of corruption offsets.
Offsets are always aligned on a 64-bit boundary,
and can include some gaps of non-corruption.
(See
.Sy bad_ranges_min_gap )
.It Sy bad_ranges_min_gap
In order to bound the size of the
.Sy bad_ranges
array, gaps of non-corruption
less than or equal to
.Sy 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.
.It Sy bad_range_sets
This array has one element per range in
.Sy 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.
.It Sy bad_range_clears
This array has one element per range in
.Sy 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.
.It Sy bad_set_bits
If this field exists, it is an array of
.Pq Ar bad data No & ~( Ns Ar 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
.Sy bad_ranges ,
and the array is ordered by offset.
Thus, the first element is the first byte in the first
.Sy bad_ranges
range, and the last element is the last byte in the last
.Sy bad_ranges
range.
.It Sy bad_cleared_bits
Like
.Sy bad_set_bits ,
but contains
.Pq Ar good data No & ~( Ns Ar bad data ) ;
that is, the bits set in the good data which are cleared in the bad data.
.It Sy bad_set_histogram
If this field exists, it is an array of counters.
Each entry counts bits set in a particular bit of a big-endian uint64 type.
The first entry counts bits
set in the high-order bit of the first byte, the 9th byte, etc, and the last
entry counts bits set of the low-order bit of the 8th byte, the 16th byte, etc.
This information is useful for observing a stuck bit in a parallel data path,
such as IDE or parallel SCSI.
.It Sy bad_cleared_histogram
If this field exists, it is an array of counters.
Each entry counts bit clears in a particular bit of a big-endian uint64 type.
The first entry counts bits
clears of the high-order bit of the first byte, the 9th byte, etc, and the
last entry counts clears of the low-order bit of the 8th byte, the 16th byte,
etc.
This information is useful for observing a stuck bit in a parallel data
path, such as IDE or parallel SCSI.
.El
.
.Sh 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, and Ioctl.
These stages may be
set on an event to describe the life cycle of a given I/O request.
.Pp
.TS
tab(:);
l l l .
Stage:Bit Mask:Operations
_:_:_
ZIO_STAGE_OPEN:0x00000001:RWFCI

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:RWF--
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:RWFCI

ZIO_STAGE_VDEV_IO_START:0x00200000:RW--I
ZIO_STAGE_VDEV_IO_DONE:0x00400000:RW--I
ZIO_STAGE_VDEV_IO_ASSESS:0x00800000:RW--I

ZIO_STAGE_CHECKSUM_VERIFY:0x01000000:R----

ZIO_STAGE_DONE:0x02000000:RWFCI
.TE
.
.Sh 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
.Sy zio_flags
payload entry.
.Pp
.TS
tab(:);
l l .
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_DONT_CACHE:0x00000800
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
.TE
.
.Sh SEE ALSO
.Xr zfs 4 ,
.Xr zed 8 ,
.Xr zpool-wait 8