The hard-disk drives (HDDs) that are installed in the server are hot-pluggable, but this capability depends on how you configure the drives. To hot-plug a drive you must take the drive offline before you can remove it. When you take the drive offline, you prevent any application from accessing the drive and remove the logical software links to the drive.
The following conditions inhibit the ability to perform hot-plugging of a drive:
The drive provides the operating system, and the operating system is not mirrored on another drive.
The drive cannot be logically isolated from the online operations of the server.
If any of these disk drive conditions are true, then you must shut down the system before you replace the drive. See Powering Down the Server.