pvmove(8)
NAME
pvmove --- move physical extents
SYNOPSIS
pvmove [--abort] [--alloc AllocationPolicy] [--atomic]
[-b|--background] [--commandprofile ProfileName] [-d|--debug]
[-h|--help] [-i|--interval Seconds] [--noudevsync] [--reportformat
{basic|json}] [-v|--verbose] [-n|--name LogicalVolume]
[SourcePhysicalVolume[:PE[-PE]...]
[DestinationPhysicalVolume[:PE[-PE]...]...]]
DESCRIPTION
pvmove allows you to move the allocated physical extents (PEs) on
SourcePhysicalVolume to one or more other physical volumes (PVs). You
can optionally specify a source LogicalVolume in which case only
extents used by that LV will be moved to free (or specified) extents on
DestinationPhysicalVolume(s). If no DestinationPhysicalVolume is
specified, the normal allocation rules for the Volume Group are used.
If pvmove gets interrupted for any reason (e.g. the machine crashes)
then run pvmove again without any PhysicalVolume arguments to restart
any moves that were in progress from the last checkpoint.
Alternatively use pvmove --abort at any time to abort. The resulting
location of logical volumes after an abort is issued depends on whether
the --atomic option was used when starting the pvmove process.
You can run more than one pvmove at once provided they are moving data
off different SourcePhysicalVolumes, but additional pvmoves will ignore
any Logical Volumes already in the process of being changed, so some
data might not get moved.
pvmove works as follows:
1. A temporary 'pvmove' Logical Volume is created to store details of
all the data movements required.
2. Every Logical Volume in the Volume Group 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 Volume Group metadata is updated on disk.
4. The first segment of the pvmove Logical Volume 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 Volume Group 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
Logical Volume is removed and the Volume Group metadata is updated so
that the Logical Volumes 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' logical volume 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 this time, an identical logical volume 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. When a
complete copy is accomplished, the temporary logical volumes are
removed, leaving behind the segments on the destination physical
volume. If an abort is issued during the move, all logical volumes
being moved will remain on the source physical volume.
OPTIONS
See lvm(8) for common options.
--abort
Abort any moves in progress. If the --atomic option was used to
start the pvmove, all logical volumes will remain on the source
physical volume. Otherwise, those segments that have completed
the move will stay on the destination physical volume, while
those that have not will remain on the source physical volume.
--atomic
Make the entire operation atomic. That is, ensure that all
affected logical volumes are moved to the destination physical
volume together; unless the move has been aborted. If the move
has been aborted, all logical volumes will remain on the source
physical volume.
--noudevsync
Disable udev synchronisation. The process will not wait for
notification from udev. It will continue irrespective of any
possible udev processing in the background. You should only use
this if udev is not running or has rules that ignore the devices
LVM2 creates.
-b, --background
Run the daemon in the background.
-i, --interval Seconds
Report progress as a percentage at regular intervals.
-n, --name LogicalVolume
Move only the extents belonging to LogicalVolume from
SourcePhysicalVolume instead of all allocated extents to the
destination physical volume(s).
Examples
To move all Physical Extents that are used by simple Logical Volumes on
/dev/sdb1 to free Physical Extents elsewhere in the Volume Group use:
pvmove /dev/sdb1
Additionally, a specific destination device /dev/sdc1 can be specified
like this:
pvmove /dev/sdb1 /dev/sdc1
To perform the action only on extents belonging to the single Logical
Volume lvol1 do this:
pvmove -n lvol1 /dev/sdb1 /dev/sdc1
Rather than moving the contents of the entire device, it is possible to
move a range of Physical Extents - for example numbers 1000 to 1999
inclusive on /dev/sdb1 - like this:
pvmove /dev/sdb1:1000-1999
A range can also be specified as start+length, so
pvmove /dev/sdb1:1000+1000
also refers to 1000 Physical Extents starting from Physical Extent
number 1000. (Counting starts from 0, so this refers to the 1001st to
the 2000th inclusive.)
To move a range of Physical Extents to a specific location (which must
have sufficient free extents) use the form:
pvmove /dev/sdb1:1000-1999 /dev/sdc1
or
pvmove /dev/sdb1:1000-1999 /dev/sdc1:0-999
If the source and destination are on the same disk, the anywhere
allocation policy would be needed, like this:
pvmove --alloc anywhere /dev/sdb1:1000-1999 /dev/sdb1:0-999
The part of a specific Logical Volume present within in a range of
Physical Extents can also be picked out and moved, like this:
pvmove -n lvol1 /dev/sdb1:1000-1999 /dev/sdc1
SEE ALSO
lvm(8), vgconvert(8) pvs(8)
Free and Open Source Software