By default the PanicSystemOnDGLoss attribute is set to 1 (true).

The attribute will cause VCS to panic the system on sudden loss of the diskgroup, when imported by VCS. In version 4.x, the resource will also need to be marked as "Critical" for the panic to occur and VCS will not panic the system if the resource is not marked critical.  The VCS Diskgroup Agent PanicSystemOnDGLoss attribute has new behavior in 5.0 which does not depend on the resource being marked critical. 

VCS will then perform an evacuation of the resource and related service group to the next surviving node. If the surviving node is unable to online the resource, no further panics are induced. The clean procedure is called and VCS stops trying to online the resource until the fault is cleared.

panic string

panic[cpu0]/thread=3000aa82cc0: forced crash dump initiated at user request

000002a101c8b850 genunix:kadmin+4a4 (b4, 0, 0, 11eec00, 5, 0)
 %l0-3: 0000000001814000 00000000011ad400 0000000000000004 0000000000000004
 %l4-7: 0000000000000438 0000000000000010 0000000000000004 0000000000000000
000002a101c8b910 genunix:uadmin+110 (5, 0, 0, ff38e000, 18898, 5)
 %l0-3: 0000000000000000 0000000000000000 00000000f6db0000 000000000000f6db
 %l4-7: 0000000000000001 0000000000000000 0000000000000000 0000030003767610

syncing file systems... 14 8 done
dumping to /dev/dsk/c5t29d0s2, offset 65536, content: kernel
100% done: 33087 pages dumped, compression ratio 3.12, dump succeeded


VCS evacuates resources

 

2009/07/23 09:37:57 VCS CRITICAL V-16-10001-1073 (wicked) DiskGroup:mydg:monitorisk Group: mydg is disabled on system: wicked. System will panic to migrate all service groups to another VCS node in system list
 

The surviving node stops attempts to online resource

VxVM vxdg ERROR V-5-1-580 Disk group mydg: Flush failed: Disk group not found
VxVM vxdg ERROR V-5-1-581 Disk group mydg: No such disk group is imported
2009/07/23 09:42:54 VCS INFO V-16-2-13068 (jerr1) Resource(mydg) - clean completed successfully.
2009/07/23 09:42:54 VCS INFO V-16-2-13071 (jerr1) Resource(mydg): reached OnlineRetryLimit(1).
2009/07/23 09:42:55 VCS ERROR V-16-1-10303 Resource mydg (Owner: unknown, Group: mysg) is FAULTED (timed out) on sys jerr1
2009/07/23 09:42:55 VCS INFO V-16-1-10493 Evaluating wicked as potential target node for group mysg
2009/07/23 09:42:55 VCS INFO V-16-1-10494 System wicked not in RUNNING state