When expanding a RAID 5 on NetWare, if the newly added drive fails during the restripe, this is considered a fault and the device and its pools are automatically deactivated. If the same partition comes back online, it finishes the restripe. If the partition fails to come back online, you must re-create the RAID to the desired size and recover from backup.
To avoid potential data loss, make sure you have a current backup before you expand the RAID 5 on NetWare.