Veritas Volume Manager 5.0 Administrator's Guide (September 2006)

410 Administering cluster functionality
Administering VxVM in cluster environments
The following is example output for the command vxdg list group1 on the master:
Group: group1
dgid: 774222028.1090.teal
import-id: 32768.1749
flags: shared
version: 140
alignment: 8192 (bytes)
ssb: on
local-activation: exclusive-write
cluster-actv-modes: node0=ew node1=off
detach-policy: local
private_region_failure: leave
copies: nconfig=2 nlog=2
config: seqno=0.1976 permlen=1456 free=1448 templen=6
loglen=220
config disk c1t0d0 copy 1 len=1456 state=clean online
config disk c1t0d0 copy 1 len=1456 state=clean online
log disk c1t0d0 copy 1 len=220
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 private_region_failure 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
Note: Shared disk groups can only be created on the master node.
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=]devicename
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).
Caution: 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.