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:

Creating a mirror of the logical volumes that you are moving
Synchronizing the logical volumes
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    FREE DISTRIBUTION 
   hdisk0   active    515        116             57..00..00..00..59 
   hdisk1   active    515        515             00..00..00..00..00

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.

Next, find a disk or disks that have the available space. In this case, hdisk1 has 515 free physical partitions, which is more than the required space of 399 physical partitions.

The only situation that is specific to rootvg is if the desired disk contains the boot image. Generally, this is the logical volume called hd5. From the following partial list of lsvg -l rootvg, this logical volume has a type of boot:

LV NAME    TYPE   Ps   PPs  PVs  LV STATE        MOUNT POINT 
hd5        boot   1    1    1    closed/syncd    N/A

To determine if the boot image is on the disk that you want to migrate, run the lslv -l command. The following example displays the output when you issue the lslv -l command:

# lslv -l hd5 
   hd5:N/A 
   PV          COPIES         IN BAND       DISTRIBUTION 
   hdisk0      001:000:000    100%          001:000:000:000:000

In this case, the boot image resides on the disk that you want to migrate. You must first move the boot image with the migratepv -l command.