Veritas Storage Foundation 5.0 for Oracle RAC Configuration Guide Extracts for HP Serviceguard Storage Management Suite, Second Edition, May 2008

Planning SGeRAC Installation and Configuration

About CVM and CFS in an SGeRAC Environment

Chapter 2

Enabling Write Access to Volumes in the Disk Groups

By default, the activation mode for shared disk groups is inactive (set to off). To create

databases on the shared volumes, enable the write access to the volumes:

• On the CVM master node, enter:

# vxdg -s import shared_disk_group

# vxvol -g shared_disk_group startall

# vxdg -g shared_disk_group set activation=sw

• On the slave nodes, enter:

# vxdg -g shared_disk_group set activation=sw

Refer to the description of disk group activation modes in the Veritas Volume Manager

Administrator’s Guide for more information.

Deporting and Importing Shared Disk Groups

Shared disk groups in an SGeRAC environment are configured for “Autoimport” at the

time of CVM startup. If the user manually deports the shared disk group on the CVM

master, the disk group is deported on all nodes. To reimport the disk group, the user

must import the disk group as a shared group from the CVM master.

• To deport a shared disk group, use the following command on the CVM master:

# vxdg deport shared_disk_group

• To import a shared disk group, use the following command on the CVM master:

# vxdg -s import shared_disk_group

• To import a disk group as a standalone disk group, deport it from the CVM master

and use the following command on any node:

# vxdg -C import shared_disk_group

• To reimport a disk group as a shared disk group, deport it from the standalone node

and use the following command on the CVM master node:

# vxdg -C -s import shared_disk_group

Reviewing Limitations of Shared Disk Groups

The cluster functionality of VxVM (CVM) does not support RAID-5 volumes or task

monitoring for shared disk groups in a cluster. These features can function in private

disk groups attached to specific nodes of a cluster. Online relayout is available provided

it does not involve RAID-5 volumes.

The boot disk group (usually aliased as bootdg) is a private group that cannot be shared

in a cluster.

CVM only provides access to raw device; it does not support shared access to file systems

in shared volumes unless you install and configure the appropriate software, such as

Veritas Cluster File System (CFS). If a shared disk group contains unsupported objects,

deport the group and reimport it as a private group on any node. Reorganize the volumes

into layouts supported for shared disk groups, and then deport and reimport the group

as a shared one.