There are instances when you must take a disk offline. If a disk is corrupted, you must disable the disk before removing it. You must also disable a disk before moving the physical disk device to another location to be connected to another system.
Taking a disk offline is only useful on systems that support hot-swap removal and insertion of disks. If a system does not support hot-swap removal and insertion of disks, you must shut down the system.
To take a disk offline
Select a disk device to disable [<address>,list,q,?] c0t2d0s2
Disable another device? [y,n,q,?] (default: n)