zinject.8

ZINJECT(8) System Manager's Manual ZINJECT(8)

zinject — ZFS Fault Injector

zinject creates artificial problems in a ZFS pool by simulating data corruption or device failures. This program is dangerous.

zinject
List injection records.
zinject -b objset:object:level:start:end [-f frequency] -amu [pool]
Force an error into the pool at a bookmark.
zinject -c id|all
Cancel injection records.
zinject -d vdev -A | pool
Force a vdev into the DEGRADED or FAULTED state.
zinject -d vdev -D latency:lanes [-T read|write] pool
Add an artificial delay to I/O requests on a particular device, such that the requests take a minimum of latency milliseconds to complete. Each delay has an associated number of lanes which defines the number of concurrent I/O requests that can be processed.

For example, with a single lane delay of 10 ms (-D 10:1), the device will only be able to service a single I/O request at a time with each request taking 10 ms to complete. So, if only a single request is submitted every 10 ms, the average latency will be 10 ms; but if more than one request is submitted every 10 ms, the average latency will be more than 10 ms.

Similarly, if a delay of 10 ms is specified to have two lanes (-D 10:2), then the device will be able to service two requests at a time, each with a minimum latency of 10 ms. So, if two requests are submitted every 10 ms, then the average latency will be 10 ms; but if more than two requests are submitted every 10 ms, the average latency will be more than 10 ms.

Also note, these delays are additive. So two invocations of -D 10:1 are roughly equivalent to a single invocation of -D 10:2. This also means, that one can specify multiple lanes with differing target latencies. For example, an invocation of -D 10:1 followed by -D 25:2 will create 3 lanes on the device: one lane with a latency of 10 ms and two lanes with a 25 ms latency.

zinject -d vdev [-e device_error] [-L label_error] [-T failure] [-f frequency] [-F] pool
Force a vdev error.
zinject -i seconds pool
Add an artificial delay during the future import of a pool. This injector is automatically cleared after the import is finished.
zinject -I [-s seconds|-g txgs] pool
Simulate a hardware failure that fails to honor a cache flush.
zinject -p function pool
Panic inside the specified function.
zinject -t -C dvas [-e device_error] [-f frequency] [-l level] [-r range] [-amq] path
Force an error into the contents of a file.
zinject -t -C dvas [-e device_error] [-f frequency] [-l level] [-amq] path
Force an error into the metadnode for a file or directory.
zinject -t mos_type -C dvas [-e device_error] [-f frequency] [-l level] [-r range] [-amqu] pool
Force an error into the MOS of a pool.

Flush the ARC before injection.
objset:object:level:start:end
Force an error into the pool at this bookmark tuple. Each number is in hexadecimal, and only one block can be specified.
dvas
Inject the given error only into specific DVAs. The mask should be specified as a list of 0-indexed DVAs separated by commas (e.g. 0,2). This option is not applicable to logical data errors such as decompress and decrypt.
vdev
A vdev specified by path or GUID.
device_error
Specify
for an ECKSUM error,
for a data decompression error,
for a data decryption error,
to flip a bit in the data after a read,
for an ECHILD error,
for an EIO error where reopening the device will succeed,
for an ENXIO error where reopening the device will fail, or
to drop the IO without executing it, and return success.

For EIO and ENXIO, the "failed" reads or writes still occur. The probe simply sets the error value reported by the I/O pipeline so it appears the read or write failed. Decryption errors only currently work with file data.

frequency
Only inject errors a fraction of the time. Expressed as a real number percentage between and .
Fail faster. Do fewer checks.
txgs
Run for this many transaction groups before reporting failure.
Print the usage message.
level
Inject an error at a particular block level. The default is .
label_error
Set the label error region to one of , , , or .
Automatically remount the underlying filesystem.
Quiet mode. Only print the handler number added.
range
Inject an error over a particular logical range of an object, which will be translated to the appropriate blkid range according to the object's properties.
seconds
Run for this many seconds before reporting failure.
type
Inject the error into I/O of this type.
, , , ,
Fundamental I/O types
All fundamental I/O types
Device probe I/O
mos_type
Set this to
for any data in the MOS,
for an object directory,
for the pool configuration,
for the block pointer list,
for the space map,
for the metaslab, or
for the persistent error log.
Unload the pool after injection.

Run zinject in debug mode.

zfs(8), zpool(8)

January 14, 2025 Debian