VERITAS Volume Manager 4.1 Migration Guide

Converting LVM to VxVM

Converting LVM Volume Groups to VxVM Disk Groups

Chapter 2 3

Converting LVM Volume Groups to VxVM Disk Groups

This section outlines the process for converting LVM volume groups to VxVM disk groups.

NOTE It is recommended that you read through this section carefully before

beginning any volume group conversion.

The conversion process involves many steps. Though there are tools to help you with the

conversion, some of these steps cannot be automated. You should be sure to understand how

the whole conversion process works, and what you will need to do in the process before

beginning a volume group conversion.

The tool used for conversion is vxvmconvert. This interactive, menu-driven program walks

you through many of the steps of the process of converting volume groups for use by VxVM.

Using vxvmconvert can reduce the downtime associated with converting from LVM to VxVM.

Without the vxvmconvert tool, the only possible method of conversion would be to take full

backups of user data, destroy the existing LVM conﬁguration leaving only raw disks, recreate

the conﬁguration in VxVM, and then reload the user data.

The vxvmconvert process converts LVM volume groups to VxVM disk groups in place. In

reality, the utility changes disks within LVM volume groups to VxVM disks by taking over the

areas of the disks used for LVM conﬁguration information, and creating the equivalent VxVM

volume conﬁguration information. User data, the portions of the disks used for ﬁle systems,

databases, etc., are not affected by the conversion.

The act of conversion changes the names by which your system refers to the logical storage.

For this reason, the conversion process is necessarily an off-line one. There can be no

application access to user data in the volume groups undergoing conversion. Access to the

LVM conﬁguration itself (the metadata of LVM) must also be limited to the conversion

process.

Volume Group Conversion Limitations

There are certain LVM volume conﬁgurations that cannot be converted to VxVM. Some of the

reasons a conversion could fail are:

• A volume group with insufﬁcient space for metadata.