Finally in vxvm 4.0 rootdg is not required This make the job of using SVM to mirroring the root disk and use vxvm to controll the other disks more nature
Now a day most storages are protected by HA-RAID. so the question: when you will need VM?
- mirror root disks, right now most root disk are not yet protected by HW_RAID, even through SAN boot is supported, since SAN Foundation SW is not part of the Solaris SW, the task is not very straightforward
- the need of controlling the shared storage (diskgroup, diskset) (deport, import ) (take, release) in failover env or RAC environment
- The need of mirror disks between arrary