Acer Altos RAIDWatch, Manual

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Array Management
71
Chapter 5
Array Management
This chapter describes how to manage a disk array system. Topics covered include the following:
• Background information about disk array management, 5.1 on page 71.
• Operating with Spare Drives, 5.2 on page 72
• Operating without spare drives, 5.3 on page 73.
• Before you start, 5.4 on page 73.
If this is your first time to manage a disk array system, we recommend that you read through section
5.1, ”Background Information”, to get basic information about disk array management. You will
need this basic knowledge to be able to effectively use Altos RAIDWatch Manager.
5.1 Background Information
Redundant Arrays of Independent Disks (RAID) is a storage technology used to improve the
processing capability of storage systems. This technology is designed to provide reliability (i.e.,
“fault tolerance”) in disk array systems and to take advantage of the performance gains multiple
disks can offer.
RAID comes with a redundancy feature that ensures fault-tolerant, uninterrupted disk storage
operations. In the event of a disk failure, disk access will still continue normally with the failure
transparent to the host system.
RAID has six levels: RAID 0 ~ 5. RAID levels 1, 3 and 5 are the most commonly used levels, while RAID
levels 2 and 4 are less popular. Appendix C , ”RAID Levels”, on page 183 gives information about
these levels, including the benefits of each.
Disk array controllers support hot-swapping where a failed drive can be replaced while the disk
array system continues to function. Spares can also be assigned so that, as soon as a drive fails, the
spare will be automatically configured into the array and reconstruction will commence.