Disk Spanning
Disk spanning allows multiple disk drives to function like one big drive. Spanning overcomes lack of disk space and simplifies storage management by combining existing resources or adding relatively inexpensive resources. For example, four 400 MB disk drives can be combined to appear to the operating system as one single 1600 MB drive.
Spanning alone does not provide reliability or performance enhancements. Spanned logical drives must have the same stripe size and must be contiguous. In the following graphic, RAID 1 array is turned into a RAID 10 array.
This controller supports a span depth of eight. That means that eight RAID 1, 3 or 5 arrays can be spanned to create one logical drive.
Spanning for RAID 10, RAID 30, or RAID 50
Level | Description |
10Configure RAID 10 by spanning two contiguous RAID 1 logical drives. The RAID 1 logical drives must have the same stripe size.
30Configure RAID 30 by spanning two contiguous RAID 3 logical drives. The RAID 3 logical drives must have the same stripe size.
50Configure RAID 50 by spanning two contiguous RAID 5 logical drives. The RAID 5 logical drives must have the same stripe size.
Note: Spanning two contiguous RAID 0 logical drives does not produce a new RAID level or add fault tolerance. It does increase the size of the logical volume and improves performance by doubling the number of spindles.
Chapter 2 Introduction to RAID | 9 |