Ubuntu Manpage: pvck - Check metadata on physical volumes

Provided by: lvm2_2.03.11-2.1ubuntu5_amd64

NAME

       pvck - Check metadata on physical volumes

SYNOPSIS

       pvck option_args position_args
           [ option_args ]

           --commandprofile String
           --config String
        -d|--debug
           --driverloaded y|n
           --dump headers|metadata|metadata_all|metadata_search
        -f|--file String
        -h|--help
           --labelsector Number
           --lockopt String
           --longhelp
           --nolocking
           --profile String
           --[pv]metadatacopies 0|1|2
        -q|--quiet
           --repair
           --repairtype pv_header|metadata|label_header
           --settings String
        -t|--test
        -v|--verbose
           --version
        -y|--yes

DESCRIPTION

pvck checks and repairs LVM metadata on PVs.

Dump options
headers
Print LVM on-disk headers and structures: label_header, pv_header, mda_header(s), and metadata text.
Warnings are printed if any values are incorrect. The label_header and pv_header both exist in a 512
byte sector, usually the second sector of the device. An mda_header exists in a 512 byte sector at
offset 4096 bytes. A second mda_header can optionally exist near the end of the device. The metadata
text exists in an area (about 1MiB by default) immediately following the mda_header sector. The metadata
text is checked but not printed (see other options).

metadata
Print the current LVM VG metadata text (or save to a file), using headers to locate the latest copy of
metadata. If headers are damaged, metadata may not be found (see metadata_search). Use --settings
"mda_num=2" to look in mda2 (the second mda at the end of the device, if used). The metadata text is
printed to stdout or saved to a file with --file.

metadata_all
List all versions of VG metadata found in the metadata area, using headers to locate metadata. Full
copies of all metadata are saved to a file with the --file option. If headers are damaged, metadata may
not be found (see metadata_search). Use --settings "mda_num=2" as above. Use -v to include descriptions
and dates when listing metadata versions.

metadata_search
List all versions of VG metadata found in the metadata area, searching common locations so metadata can
be found if headers are damaged. Full copies of all metadata are saved to a file with the --file option.
To save one specific version of metadata, use --settings "metadata_offset=<offset>", where the offset is
taken from the list of versions found. Use -v to include descriptions and dates when listing metadata
versions.

metadata_area
Save the entire text metadata area to a file without processing.

Repair options
--repair
Repair headers and metadata on a PV. This uses a metadata input file that was extracted by --dump, or a
backup file (from /etc/lvm/backup). When possible, use metadata saved by --dump from another PV in the
same VG (or from a second metadata area on the PV).

There are cases where the PV UUID needs to be specified for the PV being repaired. It is specified using
--settings "pv_uuid=<UUID>". In particular, if the device name for the PV being repaired does not match
the previous device name of the PV, then LVM may not be able to determine the correct PV UUID. When
headers are damaged on more than one PV in a VG, it is important for the user to determine the correct PV
UUID and specify it in --settings. Otherwise, the wrong PV UUID could be used if device names have been
swapped since the metadata was last written.

If a PV has no metadata areas and the pv_header is damaged, then the repair will not know to create no
metadata areas during repair. It will by default repair metadata in mda1. To repair with no metadata
areas, use --settings "mda_offset=0 mda_size=0".

There are cases where repair should be run on all PVs in the VG (using the same metadata file): if all
PVs in the VG are damaged, if using an old metadata version, or if a backup file is used instead of raw
metadata (taken from pvck dump.)

Using --repair is equivalent to running --repairtype pv_header followed by --repairtype metadata.

--repairtype pv_header
Repairs the header sector, containing the pv_header and label_header.

--repairtype metadata
Repairs the mda_header and metadata text. It requires the headers to be correct (having been undamaged
or already repaired).

--repairtype label_header
Repairs label_header fields, leaving the pv_header (in the same sector) unchanged. (repairtype pv_header
should usually be used instead.)

Settings
The --settings option controls or overrides certain dump or repair behaviors. All offset and size values
in settings are in bytes (units are not recognized.) These settings are subject to change.

mda_num=1|2
Select which metadata area should be used. By default the first metadata area (1) is used. mda1 is
always located at offset 4096. mda2, at the end of the device, often does not exist (it's not created by
default.) If mda1 is erased, mda2, if it exists, will often still have metadata.

metadata_offset=bytes
Select metadata text at this offset. Use with metadata_search to print/save one instance of metadata
text.

mda_offset=bytes mda_size=bytes
Refers to a metadata area (mda) location and size. An mda includes an mda_header and circular metadata
text buffer. Setting this forces metadata_search look for metadata in the given area instead of the
standard locations. When set to zero with repair, it indicates no metadata areas should exist.

mda2_offset=bytes mda2_size=bytes
When repairing a pv_header, this forces a specific offset and size for mda2 that should be recorded in
the pv_header.

pv_uuid=uuid
Specify the PV UUID of the device being repaired. When not specified, repair will attempt to determine
the correct PV UUID by matching a device name in the metadata.

device_size=bytes
data_offset=bytes
When repairing a pv_header, the device_size, data_offset, and pvid can all be specified directly, in
which case these values are not taken from a metadata file (where they usually come from), and the
metadata file can be omitted. data_offset is the starting location of the first physical extent (data),
which follows the first metadata area.

USAGE

       Check for metadata on a device

       pvck PV ...
           [ COMMON_OPTIONS ]
       -

       Check and print LVM headers and metadata on a device

       pvck --dump headers|metadata|metadata_all|metadata_search PV
           [ -f|--file String ]
           [    --settings String ]
           [    --[pv]metadatacopies 0|1|2 ]
           [ COMMON_OPTIONS ]
       -

       Repair LVM headers or metadata on a device

       pvck --repairtype pv_header|metadata|label_header PV
           [ -f|--file String ]
           [    --settings String ]
           [ COMMON_OPTIONS ]
       -

       Repair LVM headers and metadata on a device

       pvck --repair -f|--file String PV
           [    --settings String ]
           [ COMMON_OPTIONS ]
       -

       Common options for command:
           [    --labelsector Number ]

       Common options for lvm:
           [ -d|--debug ]
           [ -h|--help ]
           [ -q|--quiet ]
           [ -t|--test ]
           [ -v|--verbose ]
           [ -y|--yes ]
           [    --commandprofile String ]
           [    --config String ]
           [    --driverloaded y|n ]
           [    --lockopt String ]
           [    --longhelp ]
           [    --nolocking ]
           [    --profile String ]
           [    --version ]

OPTIONS

--commandprofile String
The command profile to use for command configuration. See lvm.conf(5) for more information about
profiles.

--config String
Config settings for the command. These override lvm.conf settings. The String arg uses the same
format as lvm.conf, or may use section/field syntax. See lvm.conf(5) for more information about
config.

-d|--debug ...
Set debug level. Repeat from 1 to 6 times to increase the detail of messages sent to the log file
and/or syslog (if configured).

--driverloaded y|n
If set to no, the command will not attempt to use device-mapper. For testing and debugging.

--dump headers|metadata|metadata_all|metadata_search
Dump headers and metadata from a PV for debugging and repair. Option values include: headers to
print and check LVM headers, metadata to print or save the current text metadata, metadata_all to
list or save all versions of metadata, metadata_search to list or save all versions of metadata,
searching standard locations in case of damaged headers, metadata_area to save an entire text
metadata area to a file.

-f|--file String
Metadata file to read or write.

-h|--help
Display help text.

--labelsector Number
By default the PV is labelled with an LVM2 identifier in its second sector (sector 1). This lets
you use a different sector near the start of the disk (between 0 and 3 inclusive - see
LABEL_SCAN_SECTORS in the source). Use with care.

--lockopt String
Used to pass options for special cases to lvmlockd. See lvmlockd(8) for more information.

--longhelp
Display long help text.

--nolocking
Disable locking.

--profile String
An alias for --commandprofile or --metadataprofile, depending on the command.

--[pv]metadatacopies 0|1|2
The number of metadata areas to set aside on a PV for storing VG metadata. When 2, one copy of
the VG metadata is stored at the front of the PV and a second copy is stored at the end. When 1,
one copy of the VG metadata is stored at the front of the PV. When 0, no copies of the VG
metadata are stored on the given PV. This may be useful in VGs containing many PVs (this places
limitations on the ability to use vgsplit later.)

-q|--quiet ...
Suppress output and log messages. Overrides --debug and --verbose. Repeat once to also suppress
any prompts with answer 'no'.

--repair
Repair headers and metadata on a PV.

--repairtype pv_header|metadata|label_header
Repair headers and metadata on a PV. See command description.

--settings String
Specifies command specific settings in "Key = Value" form. Combine multiple settings in quotes,
or repeat the settings option for each.

-t|--test
Run in test mode. Commands will not update metadata. This is implemented by disabling all
metadata writing but nevertheless returning success to the calling function. This may lead to
unusual error messages in multi-stage operations if a tool relies on reading back metadata it
believes has changed but hasn't.

-v|--verbose ...
Set verbose level. Repeat from 1 to 4 times to increase the detail of messages sent to stdout and
stderr.

--version
Display version information.

-y|--yes
Do not prompt for confirmation interactively but always assume the answer yes. Use with extreme
caution. (For automatic no, see -qq.)

VARIABLES


       PV
              Physical Volume name, a device path under /dev.  For commands  managing  physical  extents,  a  PV
              positional  arg  generally  accepts  a  suffix indicating a range (or multiple ranges) of physical
              extents (PEs). When the first PE is omitted, it defaults to the start of the device, and when  the
              last  PE is omitted it defaults to end.  Start and end range (inclusive): PV[:PE-PE]...  Start and
              length range (counting from 0): PV[:PE+PE]...

       String
              See the option description for information about the string content.

       Size[UNIT]
              Size is an input number that accepts an optional unit.  Input units are always treated as base two
              values, regardless of capitalization, e.g. 'k' and 'K' both refer to 1024.  The default input unit
              is specified  by  letter,  followed  by  |UNIT.   UNIT  represents  other  possible  input  units:
              bBsSkKmMgGtTpPeE.   b|B is bytes, s|S is sectors of 512 bytes, k|K is KiB, m|M is MiB, g|G is GiB,
              t|T is TiB, p|P is PiB, e|E is EiB.  (This should not be confused with the output control --units,
              where capital letters mean multiple of 1000.)

ENVIRONMENT VARIABLES

       See lvm(8) for information about environment  variables  used  by  lvm.   For  example,  LVM_VG_NAME  can
       generally be substituted for a required VG parameter.

EXAMPLES

       If  the  partition  table is corrupted or lost on /dev/sda, and you suspect there was an LVM partition at
       approximately 100 MiB, then this area of the disk can be scanned using the --labelsector parameter with a
       value of 204800 (100 * 1024 * 1024 / 512 = 204800).
       pvck --labelsector 204800 /dev/sda