VDOSTATS(8)

NAME
vdostats - get configuration and statistics from a running VDO volume

SYNOPSIS
vdostats [--verbose] [--human-readable] [--si] [--all] [--version] [ device... ]

DESCRIPTION
The vdostats utility display statistics for each configured (or specified) VDO device.

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

Device
    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)

Used
    The total number of 1K blocks used on a VDO volume (= physical blocks used * block size / 1024)

Available
    The total number of 1K blocks available on a VDO volume (= physical blocks free * block size / 1024)

Use%
    The percentage of physical blocks used on a VDO volume (= used blocks / allocated blocks * 100)

Space Saving%
    The percentage of physical blocks saved on a VDO volume (= [logical blocks used - physical blocks used] / logical blocks used)

VERBOSE OUTPUT
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.

version
    The version of these statistics.

release version
    The release version of the VDO.

data blocks used
    The number of physical blocks currently in use by a VDO volume to store data.

overhead blocks used
    The number of physical blocks currently in use by a VDO volume to store VDO metadata.

logical blocks used
    The number of logical blocks currently mapped.

physical blocks
    The total number of physical blocks allocated for a VDO volume.

logical blocks
    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)

used percent
    The percentage of physical blocks used on a VDO volume (= used blocks / allocated blocks * 100)

saving percent
    The percentage of physical blocks saved on a VDO volume (= [logical blocks used - physical blocks used] / logical blocks used)

block map cache size
    The size of the block map cache, in bytes.

write policy
    The write policy (sync or async). This is configured via vdo modify --writePolicy=policy.

block size
    The block size of a VDO volume, in bytes.

completed recovery count
    The number of times a VDO volume has recovered from an unclean shutdown.

read-only recovery count
    The number of times a VDO volume has been recovered from read-only mode (via vdo start --forceRebuild).

operating mode
    Indicates whether a VDO volume is operating normally, is in recovery mode, or is in read-only mode.

recovery progress (%)
    Indicates online recovery progress, or N/A if the volume is not in recovery mode.

compressed fragments written
    The number of compressed fragments that have been written since the VDO volume was last restarted.

compressed blocks written
    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.

compressed fragments in packer
    The number of compressed fragments being processed that have not yet been written.

slab count
    The total number of slabs.

slabs opened
    The total number of slabs from which blocks have ever been allocated.

slabs reopened
    The number of times slabs have been re-opened since the VDO was started.

journal disk full count
    The number of times a request could not make a recovery journal entry because the recovery journal was full.

journal commits requested count
    The number of times the recovery journal requested slab journal commits.

journal entries batching
    The number of journal entry writes started minus the number of journal entries written.

journal entries started
    The number of journal entries which have been made in memory.

journal entries writing
    The number of journal entries in submitted writes minus the number of journal entries committed to storage.

journal entries written
    The total number of journal entries for which a write has been issued.

journal entries committed
    The number of journal entries written to storage.

journal blocks batching
    The number of journal block writes started minus the number of journal blocks written.

journal blocks started
    The number of journal blocks which have been touched in memory.

journal blocks writing
    The number of journal blocks written (with metadatata in active memory) minus the number of journal blocks committed.

journal blocks written
    The total number of journal blocks for which a write has been issued.

journal blocks committed
    The number of journal blocks written to storage.

slab journal disk full count
    The number of times an on-disk slab journal was full.

slab journal flush count
    The number of times an entry was added to a slab journal that was over the flush threshold.

slab journal blocked count
    The number of times an entry was added to a slab journal that was over the blocking threshold.

slab journal blocks written
    The number of slab journal block writes issued.

slab journal tail busy count
    The number of times write requests blocked waiting for a slab journal write.

slab summary blocks written
    The number of slab summary block writes issued.

reference blocks written
    The number of reference block writes issued.

block map dirty pages
    The number of dirty pages in the block map cache.

block map clean pages
    The number of clean pages in the block map cache.

block map free pages
    The number of free pages in the block map cache.

block map failed pages
    The number of block map cache pages that have write errors.

block map incoming pages
    The number of block map cache pages that are being read into the cache.

block map outgoing pages
    The number of block map cache pages that are being written.

block map cache pressure
    The number of times a free page was not available when needed.

block map read count
    The total number of block map page reads.

block map write count
    The total number of block map page writes.

block map failed reads
    The total number of block map read errors.

block map failed writes
    The total number of block map write errors.

block map reclaimed
    The total number of block map pages that were reclaimed.

block map read outgoing
    The total number of block map reads for pages that were being written.

block map found in cache
    The total number of block map cache hits.

block map discard required
    The total number of block map requests that required a page to be discarded.

block map wait for page
    The total number of requests that had to wait for a page.

block map fetch required
    The total number of requests that required a page fetch.

block map pages loaded
    The total number of page fetches.

block map pages saved
    The total number of page saves.

block map flush count
    The total number of flushes issued by the block map.

invalid advice PBN count
    The number of times the index returned invalid advice

no space error count
    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.

instance
    The VDO instance.

512 byte emulation
    Indicates whether 512 byte emulation is on or off for the volume.

current VDO IO requests in progress
    The number of I/O requests the VDO is current processing.

maximum VDO IO requests in progress
    The maximum number of simultaneous I/O requests the VDO has processed.

current dedupe queries
    The number of deduplication queries currently in flight.

maximum dedupe queries
    The maximum number of in-flight deduplication queries.

dedupe advice valid
    The number of times deduplication advice was correct.

dedupe advice stale
    The number of times deduplication advice was incorrect.

dedupe advice timeouts
    The number of times deduplication queries timed out.

concurrent data matches
    The number of writes with the same data as another in-flight write.

concurrent hash collisions
    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:

    bios in
        The number of block I/O requests received by VDO.

    bios in partial
        The number of partial block I/O requests received by VDO. Applies only to 512-byte emulation mode.

    bios out
        The number of non-metadata block I/O requests submitted by VDO to the storage device.

    bios meta
        The number of metadata block I/O requests submitted by VDO to the storage device.

    bios journal
        The number of recovery journal block I/O requests submitted by VDO to the storage device.

    bios page cache
        The number of block map I/O requests submitted by VDO to the storage device.

    bios out completed
        The number of non-metadata block I/O requests completed by the storage device.

    bios meta completed
        The number of metadata block I/O requests completed by the storage device.

    bios journal completed
        The number of recovery journal block I/O requests completed by the storage device.

    bios page cache completed
        The number of block map I/O requests completed by the storage device.

    bios acknowledged
        The number of block I/O requests acknowledged by VDO.

    bios acknowledged partial
        The number of partial block I/O requests acknowledged by VDO. Applies only to 512-byte emulation mode.

    bios in progress
        The number of bios submitted to the VDO which have not yet been acknowledged.

    There are five types of flags:

    read
        The number of non-write bios (bios without the REQ_WRITE flag set)

    write
        The number of write bios (bios with the REQ_WRITE flag set)

    discard
        The number of bios with a REQ_DISCARD flag set

    flush
        The number of flush bios (bios with the REQ_FLUSH flag set)

    fua 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.

KVDO module bios used
    The current number of kernel "struct bio" structures allocated by the kernel VDO module.

KVDO module peak bio count
    The peak number of kernel "struct bio" structures allocated by the kernel VDO module, since the module was loaded.

KVDO module bytes used
    The current count of bytes allocated by the kernel VDO module.

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

read cache accesses
    The number of times VDO searched the read cache.

read cache hits
    The number of times VDO found an entry in the read cache for the desired data block, whether or not the block's contents had yet been read into memory.

read cache data hits
    The number of times VDO found an entry in the read cache for the desired data block, where the block's contents had been read into memory.

OPTIONS

--verbose
    Displays the utilization and block I/O (bios) statistics for the selected VDO devices.

--human-readable
    Displays block values in readable form (Base 2: 1 KB = 2^10 bytes = 1024 bytes).

--si
    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.

--all
    This option is only for backwards compatibility. It is now equivalent to --verbose.

--version
    Displays the vdostats version.

device...
    Specifies one or more specific volumes to report on. If this argument is omitted, vdostats will report on all devices.

EXAMPLES
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%

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

SEE ALSO
vdo(8).