Enterprise Volume Manager (Multi-OS) Version 2.0D Network Administration Guide

Enterprise Volume Manager (Multi-OS) Network Administration Guide 8–9

EVM Support for Volume Groups and HP Tru64 UNIX AdvFS Domains

• A volume group is the minimum unit of replication.

EVM works at the storage hardware level by creating clones or snapshots, called

BCVs, of HSG or HSV storage units that map directly to HP-UX physical

volumes. Since the copy process occurs at the physical level and the data on an

individual physical disk has meaning only in the larger context of the volume

group, creating a copy of any portion of a volume group requires that the entire

volume group be copied. In other words, creating a copy of a volume group that is

comprised of six physical volumes requires the replication of all six volumes.

• All physical volumes must be located on HSG or HSV storage.

For EVM to replicate a volume group, all physical volumes that comprise the

volume group must be located on HSG or HSV storage. This HSG or HSV storage

must be visible to EVM through the Management Appliance.

• EVM supports both VxFS (Veritas File System) and HFS (High-performance File

System). It does not support any other file systems.

• Volume group names must be unique across all EVM host agents.

A common EVM configuration involves the allocation of a single EVM host agent

computer as a backup server, which is used to mount and backup the replicated

volume groups from multiple source hosts. Such configurations are supported, but

if more than one replicated volume group is to be presented to the backup server at

the same time, the source volume groups that the copies are created from must

have unique names.

EVM Limitations for IBM AIX Logical Volume Manager

EVM V2.0A supports the IBM AIX Logical Volume Manager with some limitations.

These limitations are: