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

8–4 Enterprise Volume Manager (Multi-OS) Network Administration Guide
EVM Support for Volume Groups and HP Tru64 UNIX AdvFS Domains
Some important considerations for using volume groups in EVM:
• For multiple hosts in the EVM network, use the basic configuration for each host.
• Each volume group name on source hosts must be unique.
NOTE: HP recommends using a volume group name that identifies the host on which the
group resides; for example Host1VG1.
• Before running an EVM job, make sure that sufficient resources exist on each
HSG-based or HSV-based storage system to simultaneously replicate all of the
physical volumes that comprise a volume group.
Current Mapfile Requirement for HP-UX Volume Groups
EVM uses a mapfile to import a replicated HP-UX volume group. The mapfile defines
the logical volume name-to-number association for all of the logical volumes in a
volume group. Without this information, the operating system assigns default names
to all of the logical volumes in the replicated volume group and the original names are
lost. Without the original name it is difficult to associate a source volume with its
replicated copy.
EVM includes a script named Generate_Mapfiles.ksh, which generates a mapfile for
each volume group. This script closes all the logical volumes (unmounts the
filesystems) and deactivates the volume group before creating the mapfile. After
creating the mapfile, EVM reactivates the volume group and reopens the logical
volumes. This process completes within two minutes for most volume groups. The
volume group and all logical volumes in it are unavailable during this period.
Schedule this process on an as needed basis to minimize its effect on normal
operations.
You must create a mapfile for each volume group that will be replicated using EVM. If
the logical volume configuration for a volume group changes through the addition or
deletion of a logical volume, you must generate an updated mapfile using the same
process. Volume groups with invalid mapfiles are not displayed on the EVM Resource
page and cannot be used in EVM jobs.
EVM does not automatically display HP-UX volume groups on the EVM Resources
page. To display an HP-UX volume group on the Resources page, you must create the
mapfile for the volume group after installing the EVM V2.0D host agent for HP-UX,
or you must update the mapfile after changing the volume group.
Creating and Updating a Mapfile for HP-UX Volume Groups
This section shows you how to create and update a mapfile after you have installed the
EVM V2.0D host agent for HP-UX, or after you have changed the volume group.