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

vdostats - Display configuration and statistics of VDO volumes

vdostats [options ...] [device [device ...]]

vdostats displays configuration and statistics information for the given VDO devices. If no devices are given, it displays information about all VDO devices.

information to be reported.

Show help message and exit.
This option is only for backwards compatibility. It is now equivalent to --verbose.
Display block values in readable form (Base 2: 1 KB = 2^10 bytes = 1024 bytes).
Modifies the output of the --human-readable option to use SI units (Base 10: 1 KB = 10^3 bytes = 1000 bytes). If the --human-readable option is not supplied, this option has no effect.
Displays the utilization and block I/O (bios) statistics for the selected VDO devices.
Prints the vdostats version number and exits

The default output format is a table with the following columns, similar to that of the Linux df utility:

The path to the VDO volume
1K-blocks
The total number of 1K blocks allocated for a VDO volume (= physical volume size * block size / 1024)
The total number of 1K blocks used on a VDO volume (= physical blocks used * block size / 1024)
The total number of 1K blocks available on a VDO volume (= physical blocks free * block size / 1024)
The percentage of physical blocks used on a VDO volume (= used blocks / allocated blocks * 100)
The percentage of physical blocks saved on a VDO volume (= [logical blocks used - physical blocks used] / logical blocks used)

The --verbose option displays VDO device statistics in YAML format for the specified VDO devices. The following fields will continue to be reported in future releases. Management tools should not rely upon the order in which any of the statistics are reported.

The version of these statistics.
The release version of the VDO.
The number of physical blocks currently in use by a VDO volume to store data.
The number of physical blocks currently in use by a VDO volume to store VDO metadata.
The number of logical blocks currently mapped.
The total number of physical blocks allocated for a VDO volume.
The maximum number of logical blocks that can be mapped by a VDO volume.
1K-blocks
The total number of 1K blocks allocated for a VDO volume (= physical volume size * block size / 1024)
1K-blocks used
The total number of 1K blocks used on a VDO volume (= physical blocks used * block size / 1024)
1K-blocks available
The total number of 1K blocks available on a VDO volume (= physical blocks free * block size / 1024)
The percentage of physical blocks used on a VDO volume (= used blocks / allocated blocks * 100)
The percentage of physical blocks saved on a VDO volume (= [logical blocks used - physical blocks used] / logical blocks used)
The size of the block map cache, in bytes.
write policy
The write policy (sync, async, or async-unsafe). This is configured via vdo modify --writePolicy=policy.
The block size of a VDO volume, in bytes.
The number of times a VDO volume has recovered from an unclean shutdown.
The number of times a VDO volume has been recovered from read-only mode (via vdo start --forceRebuild).
Indicates whether a VDO volume is operating normally, is in recovery mode, or is in read-only mode.
Indicates online recovery progress, or N/A if the volume is not in recovery mode.
The number of compressed fragments that have been written since the VDO volume was last restarted.
The number of physical blocks of compressed data that have been written since the VDO volume was last restarted.

The remaining fields are primarily intended for software support and are subject to change in future releases; management tools should not rely upon them.

The number of compressed fragments being processed that have not yet been written.
The total number of slabs.
The total number of slabs from which blocks have ever been allocated.
The number of times slabs have been re-opened since the VDO was started.
The number of times a request could not make a recovery journal entry because the recovery journal was full.
The number of times the recovery journal requested slab journal commits.
The number of journal entry writes started minus the number of journal entries written.
The number of journal entries which have been made in memory.
The number of journal entries in submitted writes minus the number of journal entries committed to storage.
The total number of journal entries for which a write has been issued.
The number of journal entries written to storage.
The number of journal block writes started minus the number of journal blocks written.
The number of journal blocks which have been touched in memory.
The number of journal blocks written (with metadatata in active memory) minus the number of journal blocks committed.
The total number of journal blocks for which a write has been issued.
The number of journal blocks written to storage.
The number of times an on-disk slab journal was full.
The number of times an entry was added to a slab journal that was over the flush threshold.
The number of times an entry was added to a slab journal that was over the blocking threshold.
The number of slab journal block writes issued.
The number of times write requests blocked waiting for a slab journal write.
The number of slab summary block writes issued.
The number of reference block writes issued.
The number of dirty pages in the block map cache.
The number of clean pages in the block map cache.
The number of free pages in the block map cache.
The number of block map cache pages that have write errors.
The number of block map cache pages that are being read into the cache.
The number of block map cache pages that are being written.
The number of times a free page was not available when needed.
The total number of block map page reads.
The total number of block map page writes.
The total number of block map read errors.
The total number of block map write errors.
The total number of block map pages that were reclaimed.
The total number of block map reads for pages that were being written.
The total number of block map cache hits.
The total number of block map requests that required a page to be discarded.
The total number of requests that had to wait for a page.
The total number of requests that required a page fetch.
The total number of page fetches.
The total number of page saves.
The total number of flushes issued by the block map.
The number of times the index returned invalid advice
The number of write requests which failed due to the VDO volume being out of space.
read only error count
The number of write requests which failed due to the VDO volume being in read-only mode.
The VDO instance.
512 byte emulation
Indicates whether 512 byte emulation is on or off for the volume.
The number of I/O requests the VDO is current processing.
The maximum number of simultaneous I/O requests the VDO has processed.
The number of deduplication queries currently in flight.
The maximum number of in-flight deduplication queries.
The number of times deduplication advice was correct.
The number of times deduplication advice was incorrect.
The number of times deduplication queries timed out.
The number of writes with the same data as another in-flight write.
The number of writes whose hash collided with an in-flight write.
flush out
The number of flush requests submitted by VDO to the underlying storage.
write amplification ratio
The average number of block writes to the underlying storage per block written to the VDO device.

bios in...
bios in partial...
bios out...
bios meta...
bios journal...
bios page cache...
bios out completed...
bios meta completed...
bios journal completed...
bios page cache completed...
bios acknowledged...
bios acknowledged partial...
bios in progress...

These statistics count the number of bios in each category with a given flag. The categories are:
The number of block I/O requests received by VDO.
The number of partial block I/O requests received by VDO. Applies only to 512-byte emulation mode.
The number of non-metadata block I/O requests submitted by VDO to the storage device.
The number of metadata block I/O requests submitted by VDO to the storage device.
The number of recovery journal block I/O requests submitted by VDO to the storage device.
The number of block map I/O requests submitted by VDO to the storage device.
The number of non-metadata block I/O requests completed by the storage device.
The number of metadata block I/O requests completed by the storage device.
The number of recovery journal block I/O requests completed by the storage device.
The number of block map I/O requests completed by the storage device.
The number of block I/O requests acknowledged by VDO.
The number of partial block I/O requests acknowledged by VDO. Applies only to 512-byte emulation mode.
The number of bios submitted to the VDO which have not yet been acknowledged.

There are five types of flags:

The number of non-write bios (bios without the REQ_WRITE flag set)
The number of write bios (bios with the REQ_WRITE flag set)
The number of bios with a REQ_DISCARD flag set
The number of flush bios (bios with the REQ_FLUSH flag set)
The number of "force unit access" bios (bios with the REQ_FUA flag set)

Note that all bios will be counted as either read or write bios, depending on the REQ_WRITE flag setting, regardless of whether any of the other flags are set.

The current count of bytes allocated by the kernel VDO module.
The peak count of bytes allocated by the kernel VDO module, since the module was loaded.

The following example shows sample output if no options are provided:

Device             1K-blocks  Used       Available   Use% Space Saving%
/dev/mapper/my_vdo 1932562432 427698104  1504864328  22%  21%

With the --human-readable option, block counts are converted to conventional units (1 KB = 1024 bytes):

Device             Size   Used    Available   Use%   Space Saving%
/dev/mapper/my_vdo 1.8T   407.9G  1.4T        22%    21%

With the --si option as well, the block counts are reported using SI units (1 KB = 1000 bytes):

Device             Size   Used    Available   Use%    Space Saving%
/dev/mapper/my_vdo 2.0T   438G    1.5T        22%     21%

The output may be incomplete when the command is run by an unprivileged user.

vdo(8).

2020-02-18 Red Hat