A hard disk failure involving the disk partition/volume where eDirectory is located is equivalent to removing eDirectory from the server. (Fortunately, in a multi-server environment, one server can go down while the rest of the servers in the replica ring remain intact.)
To restore eDirectory after a failure of the disk partition/volume that it resides on, follow the procedures for restoring from your backup files as described in Preparing for a Restore and Restoring from Backup Files with iManager (or Restoring from Backup Files with the eMBox Client).
During the new installation, follow any instructions provided by the manufacturer to verify that the server's hard disks are working. The new hard disk should have at least the same storage capacity as the drive it replaces. Use the local server information files to verify configuration information.
NOTE: If you do not have backup files for the server, use the XBrowse tool to query eDirectory to help you recover server information. You must do this before you remove the Server object or any associated objects from the tree. XBrowse and additional information are available from Novell Support, Technical Information Document #2960653.