Server Administrator Storage Management 8.2 User’s Guide

If the failed disk is part of a redundant virtual disk, then the disk failure will not result in data loss. You must replace the failed disk immediately, however, as additional disk failures can cause data loss.

If the redundant virtual disk has a hot spare assigned to it, then the data from the failed disk is rebuilt onto the hot spare. After the rebuild, the former hot spare functions as a regular physical disk and the virtual disk is left without a hot spare. In this case, you must replace the failed disk and assign the replacement disk as a hot spare.