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In the first example, the cplv command copies data from the existing logical volume
oldlv. It creates a new logical volume that it calls newlv (-y) in the volume group
datavg (-v). If you omit the -v option, the volume group to which the existing
logical volume belongs receives the new logical volume. When the cplv command
creates a new logical volume, it creates the new volume with exactly the same
characteristics as the existing logical volume.
In the second example, the cplv command copies data from existing logical volume
oldlv to existing logical volume existinglv (-e). When you use the -e option, it
overwrites the existing target-logical volume with the data from the source-logical
volume. When you use the -e option, it maintains the characteristics of the existing
target-logical volume. Take care when you use this option.
The cplv command is a good method for copying or migrating a single logical
volume. Sometimes, however, you might need to migrate all the data from a
physical volume.
Using mirroring to migrate data
Use the following information as guide for how to use the mirroring function of
logical volume manager (LVM) to migrate data. Mirroring can only be used on
logical volumes. It cannot be used for physical volumes.
Mirroring is an LVM task that you perform only on logical volumes to migrate data.
The following example shows how to create a mirror copy of a logical volume using
the mklvcopy command:
The mklvcopy command options specify the following values:
(-e m) To use minimum inter-disk allocation policy
(-s y)
(-k)
datalv The name of the logical volume where you want to start a mirroring
2
hdisk3 and hdisk7
hdisk3 The physical volume that already holds the data of datalv
hdisk7 The physical volume that will hold the mirror copy and where you want to
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DS8000 User's Guide
# cplv -v datavg -y newlv oldlv
# cplv -e existinglv oldlv
# mklvcopy -e m -s y -k datalv 2 hdisk3 hdisk7
.
.
.
# splitlvcopy -y splitlv datalv 1
To strictly allocate mirror copies on separate physical volumes
To synchronize new copies immediately
operation
The number of copies that you want to make of the data (a maximum of 3)
The physical volumes where the logical volume resides
move the data
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