Online Data Relocation - Red Hat Cluster Suite 4.7 Cluster Logical Volume Manager Manual

You can control which devices LVM scans by setting up filters in the lvm.conf configuration file. The
filters consist of a series of simple regular expressions that get applied to the device names in the /
dev directory to decide whether to accept or reject each block device found.
The following examples show the use of filters to control which devices LVM scans. Note that some of
these examples do not necessarily represent best practice, as the regular expressions are matched
freely against the complete pathname. For example, a/loop/ is equivalent to a/.*loop.*/ and
would match /dev/solooperation/lvol1.
The following filter adds all discovered devices, which is the default behavior as there is no filter
configured in the configuration file:
filter = [ "a/.*/" ]
The following filter removes the cdrom device in order to avoid delays if the drive contains no media:
filter = [ "r|/dev/cdrom|" ]
The following filter adds all loop and removes all other block devices:
filter = [ "a/loop.*/", "r/.*/" ]
The following filter adds all loop and IDE and removes all other block devices:
filter =[ "a|loop.*|", "a|/dev/hd.*|", "r|.*|" ]
The following filter adds just partition 8 on the first IDE drive and removes all other block devices:
filter = [ "a|^/dev/hda8$|", "r/.*/" ]
For more information on the lvm.conf file, see
lvm.conf(5) man page.

4.7. Online Data Relocation

You can move data while the system is in use with the pvmove command.
The pvmove command breaks up the data to be moved into sections and creates a temporary mirror
to move each section. For more information on the operation of the pvmove command, see the
pvmove(8) man page.
Because the pvmove command uses mirroring, it is not cluster-aware and needs exclusive access
to a volume. For information on activating logical volumes on individual nodes in a cluster, see
Section 4.8, "Activating Logical Volumes on Individual Nodes in a
The following command moves all allocated space off the physical volume /dev/sdc1 to other free
physical volumes in the volume group:
Appendix B, The LVM Configuration Files
Cluster".
Online Data Relocation
and the
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