LSI MegaRAID Express 500 - Manual (Page 28)

MegaRAID Express 500 Hardware Guide 14
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
10 Configure RAID 10 by spanning two contiguous RAID 1 logical drives.
The RAID 1 logical drives must have the same stripe size.
30 Configure RAID 30 by spanning two contiguous RAID 3 logical drives.
The RAID 3 logical drives must have the same stripe size.
50 Configure 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.