Using a Hot-Spare
A Hot-Spare helps ensure RAID system reliability and uptime. It gives the RAID controller a drive that can be automatically used to rebuild RAID data in the event of another drive problem or failure.
If you have a RAID5 system, consider migrating to RAID6 instead of simply assigning a hot-spare. This provides additional reliability as a second set of parity information is available. There are instances where this is not practical - for example, if your system includes two RAID5 arrays, or perhaps a RAID5 or a RAID1 and the number of additional drives you can fit is limited. In this instance, if you can only fit one additional drive, the use of a Global hot-spare is recommended.
The instructions below are based on a system with an Intel or LSI hardware RAID controller or module, and the Intel RAID Web Console 2 (RWC 2) or LSI MegaRAID Storage Manager (MSM).
Tip: If you have recently replaced a failed hard drive and the RAID array has not automatically started the rebuild process, follow the instructions below. This is likely to happen on an Intel SRCSASRB or Intel SRCSATAWB controller as these do not automatically rebuild onto unassigned drives unless configured to do so.
These instructions assume that you have already fitted the hot-spare drive and have rebooted the system to do so, hence performing the configuration using the RAID BIOS. If your system isn't running Windows you can also use this method to perform the configuration; if you are running VMWare consider setting up your VMWare hosts for Remote RAID Web Console configuration.