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ZPOOL-EVENTS(8) System Manager's Manual ZPOOL-EVENTS(8) 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 pa- rameter. 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 mod- ule 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 parameter. config_sync Issued every time a vdev change have been done to the pool. zpool Issued when a pool cannot be imported. pool_create Issued when a pool is created. pool_destroy Issued when a pool is destroyed. pool_export Issued when a pool is exported. pool_import Issued when a pool is imported. pool_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 de- tected. 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 in- creased. 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_remove_aux Issued when an auxiliary vdev is removed. vdev_remove_dev Issued when a specific device is removed from a vdev. 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. vdev_add Issued when a vdev is added to a pool. vdev_attach Issued when a vdev is attached to a mirror or raidz vdev type. vdev_online Issued when an offline vdev is brought online 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. errorscrub_start Issued when a errorscrub is started on a pool. errorscrub_finish Issued when a pool has finished errorscrubbing. errorscrub_abort Issued when a errorscrub is aborted on a pool. errorscrub_resume Issued when a errorscrub is resumed on a pool. errorscrub_paused Issued when a errorscrub is paused on a pool. trim_start Issued when a trim is started on a pool. trim_finish Issued when a pool has finished trimbing. trim_cancel Issued when a trim is canceled on a pool. trim_resume Issued when a trim is resumed on a pool. trim_suspend Issued when a trim is suspend on a pool. authentication Issued when there is a decryption / authentication er- ror. config_cache_write Issued when the config cache file cannot be written. bootfs_vdev_attach Issued when a vdev is attached to a root pool with the bootfs property set. sitout Issued when a RAIDZ or DRAID vdev triggers the autosit logic. This logic detects when a disk in such a vdev is significantly slower than its peers, and sits them out temporarily to preserve the performance of the pool. 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 speci- fied 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_priority The queue priority of the I/O request. See the I/O PRIORITIES section for a full list of all the I/O prior- ities. zio_tyoe The type of the I/O request. See the I/O TYPES section for a full list of all the I/O types. 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 perfor- mance. 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 in- formation 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 corre- sponds a byte whose offset is in a range in bad_ranges, and the array is ordered by offset. Thus, the first el- ement 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 be- low. The individual stages are used to construct these basic I/O opera- tions: 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_ALLOC_THROTTLED 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 I/O TYPES Every I/O request in the pipeline has a single type value. This value de- scribes the kind of low-level work the I/O represents. This value will be set in an event as a zio_type payload entry. Type Value Description -------------------------------------------------- ZIO_TYPE_NULL 0x0 internal I/O sync point ZIO_TYPE_READ 0x1 data read ZIO_TYPE_WRITE 0x2 data write ZIO_TYPE_FREE 0x3 block free ZIO_TYPE_CLAIM 0x4 block claim (ZIL replay) ZIO_TYPE_FLUSH 0x5 disk cache flush request ZIO_TYPE_TRIM 0x6 trim (discard) I/O PRIORITIES Every I/O request in the pipeline has a single priority value. This value is used by the queuing code to decide which I/O to issue next. This value will be set in an event as a zio_priority payload entry. Type Value Description ---------------------------------------------------------------------- ZIO_PRIORITY_SYNC_READ 0x0 ZIO_PRIORITY_SYNC_WRITE 0x1 ZIL ZIO_PRIORITY_ASYNC_READ 0x2 prefetch ZIO_PRIORITY_ASYNC_WRITE 0x3 spa_sync() ZIO_PRIORITY_SCRUB 0x4 asynchronous scrub/resilver reads ZIO_PRIORITY_REMOVAL 0x5 reads/writes for vdev removal ZIO_PRIORITY_INITIALIZING 0x6 initializing I/O ZIO_PRIORITY_TRIM 0x7 trim I/O (discard) ZIO_PRIORITY_REBUILD 0x8 reads/writes for vdev rebuild ZIO_PRIORITY_NOW 0xa non-queued i/os (e.g. free) SEE ALSO zfs(4), zed(8), zpool-wait(8) FreeBSD ports 15.1 July 3, 2025 ZPOOL-EVENTS(8)
NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EVENTS | PAYLOADS | I/O STAGES | I/O FLAGS | I/O TYPES | I/O PRIORITIES | SEE ALSO
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