Using The Migratepv Command - IBM DS8000 User Manual

Using the migratepv command

Use the following information as a guide for how to use the logical volume
manager (LVM) migratepv command to migrate data that is associated with
physical volumes.
You can use the LVM migratepv command to migrate data that is associated with
physical volumes.
The following examples show how to use the migratepv command.
# migratepv hdisk1 hdisk2
# migratepv -l datalv hdisk3 hdisk9
In the example, all data migrates from hdisk1 to hdisk2. The migratepv command
updates all LVM references. From the time that the command completes, the LVM
no longer uses hdisk1 to access data that was previously stored there. As the data
is physically moved, the target physical volume must have enough spare physical
volumes to accommodate data from the source physical volumes. After this
command completes, you can remove the source-physical volume from the volume
group.
To avoid disrupting users, use the migratepv command while the system is active.
The migratepv command migrates data by performing the following actions:
v Creating a mirror of the logical volumes that you are moving
v Synchronizing the logical volumes
v Removing the original logical volume
You can use the migratepv command to move data from one physical volume to
another physical volume within the same volume group. The following usage
parameters apply to this command:
migratepv [-i] [-l LVname] SourcePV DestinationPV...
Note: You can specify more than one destination physical volume.
First, identify the source disk from which you want to migrate the data. Then,
identify the target disk to which you want to migrate the data. You can only
migrate to disks that are already in the rootvg volume group. To get a list of disks
that are already in the rootvg volume group, run the lsvg -p rootvg command. The
following example displays output when you issue the lsvg -p rootvg command:
# lsvg -p rootvg
rootvg:
PV_NAME PV STATE TOTAL PPs FREE PPs
hdisk0 active
hdisk1 active
Now, determine the space that is currently in use on the disk that you want to
migrate. This is the total physical partitions (PPs) value minus the free PPs value
for the desired disk. In the preceding example, refer to hdisk0, which is using (515
- 116) PPs or 399 physical partitions.
FREE DISTRIBUTION
515 116
515 515
Chapter 9. Migrating data to a storage unit
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