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.

List injection records.
zinject -b objset:object:level:blkd [-f frequency] [-amu] pool
Force an error into the pool at a bookmark.
zinject -c <id | all>
Cancel injection records.
zinject -d vdev -A <degrade|fault> pool
Force a vdev into the DEGRADED or FAULTED state.
zinject -d vdev -D latency:lanes pool

Add an artificial delay to IO 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 IO 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 IO 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', is roughly equivalent to a single invocation of '-D 10:2'. This also means, 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 [-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 data [-C dvas] [-e device_error] [-f frequency] [-l level] [-r range] [-amq] path
Force an error into the contents of a file.
zinject -t dnode [-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.
Force an error into the pool at this bookmark tuple. Each number is in hexadecimal, and only one block can be specified.
Inject the given error only into specific DVAs. The mask should be specified as a list of 0-indexed DVAs separated by commas (ex. '0,2'). This option is not applicable to logical data errors such as decompress and decrypt.
A vdev specified by path or GUID.
Specify checksum for an ECKSUM error, decompress for a data decompression error, decrypt for a data decryption error, corrupt to flip a bit in the data after a read, dtl for an ECHILD error, io for an EIO error where reopening the device will succeed, or nxio for an ENXIO error where reopening the device will fail. 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.
Only inject errors a fraction of the time. Expressed as a real number percentage between 0.0001 and 100.
Fail faster. Do fewer checks.
Run for this many transaction groups before reporting failure.
Print the usage message.
Inject an error at a particular block level. The default is 0.
Set the label error region to one of nvlist, pad1, pad2, or uber.
Automatically remount the underlying filesystem.
Quiet mode. Only print the handler number added.
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.
Run for this many seconds before reporting failure.
Set the failure type to one of all, claim, free, read, or write.
Set this to mos for any data in the MOS, mosdir for an object directory, config for the pool configuration, bpobj for the block pointer list, spacemap for the space map, metaslab for the metaslab, or errlog for the persistent error log.
Unload the pool after injection.

Run zinject in debug mode.

This man page was written by Darik Horn <dajhorn@vanadac.com> excerpting the zinject usage message and source code.

zpool(8), zfs(8)

August 24, 2020 OpenZFS