About nbu_snap
The snapshot method is for Solaris clients only. It is for making copy-on-write snapshots for UFS or VxFS file systems.
The information in this section applies to either Standard or FlashBackup policy types.
nbu_snap is not supported in clustered file systems. It is not supported as the selected snapshot method or as the default snapctl driver when you configure FlashBackup in the earlier manner.
See Configuring FlashBackup policy for backward compatibility (UNIX only).
An alternative copy-on-write snapshot method for clustered file systems is VxFS_Snapshot with a FlashBackup policy.
nbu_snap does not support VxVM volumes that belong to a shared disk group.