Veritas Volume Manager 5.0.1 Migration Guide, HP-UX 11i v3, First Edition, November 2009

The first and simple logical volume takes less time to convert than the striped

volume. However, for the striped volume, 50 disks need to be checked. Also,

the complexity of reproducing the VxVM commands to set up the striped

volumes requires more VxVM commands to be generated to represent more

smaller sub-disks representing the same amount of space.

Another factor in converting stripes is that stripes create more work for the

converter. In some cases, stripes require 1GB volume, although only the

metadata is being changed. In other cases, where there are more physical disks

in one volume than another, there is more metadata to deal with. The converter

has to read every physical extent map to ensure there are no holes in the

volume; if holes are found, the converter maps around them.

■ Number of volumes. While it takes longer to convert one 64GB volume than

one 2GB volume, it also takes longer to convert 64 1GB volumes than one 64GB

volume, providing that the volumes are of similar type.

■ Mirrored volumes. Mirrored volumes typically do not take more time to convert

than simple volumes. Volumes that are mirrored and striped at the same time

would take longer, but LVM currently does not allow this.

Currently, after conversion, mirrored volumes are not automatically

synchronized because a large mirror could take hours to complete.

For example, in tests, a 150GB volume group consisting of 20 simple logical

volumes takes approximately 35-40 minutes to convert. In contrast, the same

volume group (150GB) consisting of mirrored volumes that need to be

synchronized can take 30-40 hours to convert.

Note: If you convert mirrored volumes, you must synchronize them in a separate

step.

Non-interactive conversion of volume groups

The vxvmconvert utility is an interactive command. You can also use the

vxautoanalysis command and the vxautoconvert command to perform

non-interactive analysis and conversion of LVM volume groups. The

vxautorollback command also lets you reverse the conversion, and turn a VxVM

disk group back into an LVM volume group.

Note: This release only supports the conversion of LVM version 1 volume groups

to VxVM. It does not support the conversion of LVM version 2 volume groups.

Converting LVM to VxVM

Non-interactive conversion of volume groups