Veritas Volume Manager 5.1 SP1 Administrator"s Guide (5900-1506, April 2011)

log disk c1t0d0 copy 1 len=220

Note that the flags field is set to shared. The output for the same command when

run on a slave is slightly different. The local-activation and

cluster-actv-modes fields display the activation mode for this node and for each

node in the cluster respectively. The detach-policy and dg-fail-policy fields

indicate how the cluster behaves in the event of loss of connectivity to the disks,

and to the configuration and log copies on the disks.

Creating a shared disk group

You can run the command to create a shared disk group on a master node or a

slave node. If you create the disk group on a slave node, the command is shipped

to the master and executed on the master.

If the cluster software has been run to set up the cluster, a shared disk group can

be created using the following command:

# vxdg -s init diskgroup [diskname=]devicenames

where diskgroup is the disk group name, diskname is the administrative name

chosen for a VM disk, and devicename is the device name (or disk access name).

Warning: The operating system cannot tell if a disk is shared. To protect data

integrity when dealing with disks that can be accessed by multiple systems, use

the correct designation when adding a disk to a disk group. VxVM allows you to

add a disk that is not physically shared to a shared disk group if the node where

the disk is accessible is the only node in the cluster. However, this means that

other nodes cannot join the cluster. Furthermore, if you attempt to add the same

disk to different disk groups (private or shared) on two nodes at the same time,

the results are undefined. Perform all configuration on one node only, and

preferably on the master node.

Importing disk groups as shared

You can import shared disk groups on a master node or a slave node. If you run

the command to import the shared disk group on a slave node, the command is

shipped to the master and executed on the master.

Disk groups can be imported as shared using the vxdg -s import command. If

the disk groups are set up before the cluster software is run, the disk groups can

be imported into the cluster arrangement using the following command:

455Administering cluster functionality (CVM)

Administering VxVM in cluster environments