Disk groups stoping

Hi

I installed veritas 6.1 on redhat 6.4 64bit  and vom 6.0 and created disk groups and volumes  and then service groups failover and mounted the volumes in the service groups.

When i restarted node1  the service groups failover good to node2 and when i restarted node2 the failover working good and failover but if i tray to do that mounal switch some service groups failover and others not failover and the state for diskgroups in host stoping and the volume too .

Please help

Regards