Description of the different events generated by the ZFS
stack.
Most of these don't have any description. The events generated by
ZFS have never been publicly documented. What is here is intended as a
starting point to provide documentation for all possible events.
To view all events created since the loading of the ZFS
infrastructure (i.e, "the module"), run
zpool events
to get a short list, and
zpool events -v
to get a full detail of the events and what information is
available about it.
This man page lists the different subclasses that are issued in
the case of an event. The full event name would be
ereport.fs.zfs.SUBCLASS, but we only list the last part here.
checksum
Issued when a checksum error have 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.
delay
Issued when an I/O was slow to complete as defined by the
zio_delay_max module option.
config.sync
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 readded).
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 have finished scrubbing.
bootfs.vdev.attach
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
pool(8) (
failmode property) 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
zpool(8) under
Virtual Devices 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 completed for the specified
vdev.
vdev_delta_ts
The time since the last I/O 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 checkum 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.
zio_object
The object number for a given I/O.
zio_level
The block level for a given I/O.
zio_blkid
The block ID for a given I/O.
zio_err
The errno for a failure when handling a given I/O.
zio_offset
The offset in bytes of where to write the I/O for the
specified vdev.
zio_size
The size in bytes of the I/O.
zio_flags
The current flags describing how the I/O 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 in ticks (HZ) required for the block layer to
service the I/O. Unlike zio_delta this does not include any vdev
queuing time and is therefore solely a measure of the block layer performance.
On most modern Linux systems HZ is defined as 1000 making a tick equivalent to
1 millisecond.
zio_timestamp
The time when a given I/O was submitted.
zio_delta
The time required to service a given I/O.
prev_state
The previous state of the vdev.
cksum_expected
The expected checksum value.
cksum_actual
The actual/current checksum value.
cksum_algorithm
Checksum algorithm used. See
zfs(8) for more
information on checksum algorithms available.
cksum_byteswap
Checksum value is byte swapped.
bad_ranges
Checksum bad offset ranges.
bad_ranges_min_gap
Checksum allowed minimum gap.
bad_range_sets
Checksum for each range the number of bits set.
bad_range_clears
Checksum for each range the number of bits cleared.
bad_set_bits
Checksum array of bits set.
bad_cleared_bits
Checksum array of bits cleared.
bad_set_histogram
Checksum histogram of set bits by bit number in a 64-bit
word.
bad_cleared_histogram
Checksum histogram of cleared bits by bit number in a
64-bit word.
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.
| Stage |
Bit Mask |
Operations |
|
|
|
| ZIO_STAGE_OPEN |
0x00000001 |
RWFCI |
| ZIO_STAGE_READ_BP_INIT |
0x00000002 |
R---- |
| ZIO_STAGE_FREE_BP_INIT |
0x00000004 |
--F-- |
| ZIO_STAGE_ISSUE_ASYNC |
0x00000008 |
RWF-- |
| ZIO_STAGE_WRITE_BP_INIT |
0x00000010 |
-W--- |
| ZIO_STAGE_CHECKSUM_GENERATE |
0x00000020 |
-W--- |
| ZIO_STAGE_NOP_WRITE |
0x00000040 |
-W--- |
| ZIO_STAGE_DDT_READ_START |
0x00000080 |
R---- |
| ZIO_STAGE_DDT_READ_DONE |
0x00000100 |
R---- |
| ZIO_STAGE_DDT_WRITE |
0x00000200 |
-W--- |
| ZIO_STAGE_DDT_FREE |
0x00000400 |
--F-- |
| ZIO_STAGE_GANG_ASSEMBLE |
0x00000800 |
RWFC- |
| ZIO_STAGE_GANG_ISSUE |
0x00001000 |
RWFC- |
| ZIO_STAGE_DVA_ALLOCATE |
0x00002000 |
-W--- |
| ZIO_STAGE_DVA_FREE |
0x00004000 |
--F-- |
| ZIO_STAGE_DVA_CLAIM |
0x00008000 |
---C- |
| ZIO_STAGE_READY |
0x00010000 |
RWFCI |
| ZIO_STAGE_VDEV_IO_START |
0x00020000 |
RW--I |
| ZIO_STAGE_VDEV_IO_DONE |
0x00040000 |
RW--I |
| ZIO_STAGE_VDEV_IO_ASSESS |
0x00080000 |
RW--I |
| ZIO_STAGE_CHECKSUM_VERIFY0 |
0x00100000 |
R---- |
| ZIO_STAGE_DONE |
0x00200000 |
RWFCI |
Every I/O 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 an 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_DONT_CACHE |
0x00000800 |
| ZIO_FLAG_NODATA |
0x00001000 |
| ZIO_FLAG_INDUCE_DAMAGE |
0x00002000 |
| ZIO_FLAG_IO_RETRY |
0x00004000 |
| ZIO_FLAG_PROBE |
0x00008000 |
| ZIO_FLAG_TRYHARD |
0x00010000 |
| ZIO_FLAG_OPTIONAL |
0x00020000 |
| ZIO_FLAG_DONT_QUEUE |
0x00040000 |
| ZIO_FLAG_DONT_PROPAGATE |
0x00080000 |
| ZIO_FLAG_IO_BYPASS |
0x00100000 |
| ZIO_FLAG_IO_REWRITE |
0x00200000 |
| ZIO_FLAG_RAW |
0x00400000 |
| ZIO_FLAG_GANG_CHILD |
0x00800000 |
| ZIO_FLAG_DDT_CHILD |
0x01000000 |
| ZIO_FLAG_GODFATHER |
0x02000000 |
| ZIO_FLAG_NOPWRITE |
0x04000000 |
| ZIO_FLAG_REEXECUTED |
0x08000000 |
| ZIO_FLAG_DELEGATED |
0x10000000 |
| ZIO_FLAG_FASTWRITE |
0x20000000 |