Ubuntu Manpage: pvmove — Move extents from one physical volume to another

Provided by: lvm2_2.03.22-1ubuntu2_amd64

NAME

       pvmove — Move extents from one physical volume to another

SYNOPSIS

       pvmove position_args
           [ option_args ]
           [ position_args ]

DESCRIPTION

       pvmove  moves  the  allocated  physical  extents  (PEs)  on  a  source  PV  to one or more
       destination PVs.  You can optionally specify a source LV in which case only  extents  used
       by  that  LV  will  be  moved  to free (or specified) extents on the destination PV. If no
       destination PV is specified, the normal allocation rules for the VG are used.

       If pvmove is interrupted for any reason (e.g. the machine crashes) then run  pvmove  again
       without  any  PV  arguments  to restart any operations that were in progress from the last
       checkpoint. Alternatively, use the abort option at any time to abort  the  operation.  The
       resulting location of LVs after an abort depends on whether the atomic option was used.

       More  than  one  pvmove can run concurrently if they are moving data from different source
       PVs, but additional pvmoves will ignore any LVs already in the process of  being  changed,
       so some data might not get moved.

USAGE

       Move PV extents.

       pvmove PV
           [ -A|--autobackup y|n ]
           [ -n|--name LV ]
           [    --alloc contiguous|cling|cling_by_tags|normal|anywhere|inherit ]
           [    --atomic ]
           [    --noudevsync ]
           [    --reportformat basic|json|json_std ]
           [ COMMON_OPTIONS ]
           [ PV ... ]

       Continue or abort existing pvmove operations.

       pvmove
           [ COMMON_OPTIONS ]

       Common options for command:
           [ -b|--background ]
           [ -i|--interval Number ]
           [    --abort ]

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

OPTIONS

--abort
Abort any pvmove operations in progress. If a pvmove was started with the --atomic
option, then all LVs will remain on the source PV. Otherwise, segments that have
been moved will remain on the destination PV, while unmoved segments will remain on
the source PV.

--alloc contiguous|cling|cling_by_tags|normal|anywhere|inherit
Determines the allocation policy when a command needs to allocate Physical Extents
(PEs) from the VG. Each VG and LV has an allocation policy which can be changed
with vgchange/lvchange, or overridden on the command line. normal applies common
sense rules such as not placing parallel stripes on the same PV. inherit applies
the VG policy to an LV. contiguous requires new PEs be placed adjacent to existing
PEs. cling places new PEs on the same PV as existing PEs in the same stripe of the
LV. If there are sufficient PEs for an allocation, but normal does not use them,
anywhere will use them even if it reduces performance, e.g. by placing two stripes
on the same PV. Optional positional PV args on the command line can also be used
to limit which PVs the command will use for allocation. See lvm(8) for more
information about allocation.

--atomic
Makes a pvmove operation atomic, ensuring that all affected LVs are moved to the
destination PV, or none are if the operation is aborted.

-A|--autobackup y|n
Specifies if metadata should be backed up automatically after a change. Enabling
this is strongly advised! See vgcfgbackup(8) for more information.

-b|--background
If the operation requires polling, this option causes the command to return before
the operation is complete, and polling is done in the background.

--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(5) settings. The String
arg uses the same format as lvm.conf(5), 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).

--devices PV
Restricts the devices that are visible and accessible to the command. Devices not
listed will appear to be missing. This option can be repeated, or accepts a comma
separated list of devices. This overrides the devices file.

--devicesfile String
A file listing devices that LVM should use. The file must exist in
/etc/lvm/devices/ and is managed with the lvmdevices(8) command. This overrides
the lvm.conf(5) devices/devicesfile and devices/use_devicesfile settings.

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

-h|--help
Display help text.

-i|--interval Number
Report progress at regular intervals.

--journal String
Record information in the systemd journal. This information is in addition to
information enabled by the lvm.conf log/journal setting. command: record
information about the command. output: record the default command output. debug:
record full command debugging.

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

--longhelp
Display long help text.

-n|--name String
Move only the extents belonging to the named LV.

--nohints
Do not use the hints file to locate devices for PVs. A command may read more
devices to find PVs when hints are not used. The command will still perform
standard hint file invalidation where appropriate.

--nolocking
Disable locking. Use with caution, concurrent commands may produce incorrect
results.

--noudevsync
Disables udev synchronization. The process will not wait for notification from
udev. It will continue irrespective of any possible udev processing in the
background. Only use this if udev is not running or has rules that ignore the
devices LVM creates.

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

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

--reportformat basic|json|json_std
Overrides current output format for reports which is defined globally by the
report/output_format setting in lvm.conf(5). basic is the original format with
columns and rows. If there is more than one report per command, each report is
prefixed with the report name for identification. json produces report output in
JSON format. json_std produces report output in JSON format which is more compliant
with JSON standard. See lvmreport(7) for more information.

-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: 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.

NOTES

pvmove works as follows:

1. A temporary 'pvmove' LV is created to store details of all the data movements required.

2. Every LV in the VG is searched for contiguous data that need moving according to the
command line arguments. For each piece of data found, a new segment is added to the end
of the pvmove LV. This segment takes the form of a temporary mirror to copy the data from
the original location to a newly allocated location. The original LV is updated to use
the new temporary mirror segment in the pvmove LV instead of accessing the data directly.

3. The VG metadata is updated on disk.

4. The first segment of the pvmove LV is activated and starts to mirror the first part of
the data. Only one segment is mirrored at once as this is usually more efficient.

5. A daemon repeatedly checks progress at the specified time interval. When it detects
that the first temporary mirror is in sync, it breaks that mirror so that only the new
location for that data gets used and writes a checkpoint into the VG metadata on disk.
Then it activates the mirror for the next segment of the pvmove LV.

6. When there are no more segments left to be mirrored, the temporary LV is removed and
the VG metadata is updated so that the LVs reflect the new data locations.

Note that this new process cannot support the original LVM1 type of on-disk metadata.
Metadata can be converted using vgconvert(8).

If the --atomic option is used, a slightly different approach is used for the move.
Again, a temporary 'pvmove' LV is created to store the details of all the data movements
required. This temporary LV contains all the segments of the various LVs that need to be
moved. However, in this case, an identical LV is allocated that contains the same number
of segments and a mirror is created to copy the contents from the first temporary LV to
the second. After a complete copy is made, the temporary LVs are removed, leaving behind
the segments on the destination PV. If an abort is issued during the move, all LVs being
moved will remain on the source PV.

EXAMPLES

       Move all physical extents that are used by simple LVs on the specified PV to free physical
       extents elsewhere in the VG.
       pvmove /dev/sdb1

       Use a specific destination PV when moving physical extents.
       pvmove /dev/sdb1 /dev/sdc1

       Move extents belonging to a single LV.
       pvmove -n lvol1 /dev/sdb1 /dev/sdc1

       Rather  than  moving  the  contents of an entire device, it is possible to move a range of
       physical extents, for example numbers 1000 to 1999 inclusive on the specified PV.
       pvmove /dev/sdb1:1000-1999

       A range of physical extents to  move  can  be  specified  as  start+length.  For  example,
       starting from PE 1000. (Counting starts from 0, so this refers to the 1001st to the 2000th
       PE inclusive.)
       pvmove /dev/sdb1:1000+1000

       Move a range of physical extents to  a  specific  PV  (which  must  have  sufficient  free
       extents).
       pvmove /dev/sdb1:1000-1999 /dev/sdc1

       Move a range of physical extents to specific new extents on a new PV.
       pvmove /dev/sdb1:1000-1999 /dev/sdc1:0-999

       If  the  source  and  destination  are on the same disk, the anywhere allocation policy is
       needed.
       pvmove --alloc anywhere /dev/sdb1:1000-1999 /dev/sdb1:0-999

       The part of a specific LV present within in a range of physical extents can also be picked
       out and moved.
       pvmove -n lvol1 /dev/sdb1:1000-1999 /dev/sdc1