Spanned Arrays: Raid Levels 10 And 50 - HP P3410A - NetRAID 1M RAID Controller Installation And Configuration Manual

Chapter 2

Spanned Arrays: RAID Levels 10 and 50

With HP NetRAID-1M and 2M adapters, array spanning allows the capacity of
up to eight basic arrays to be combined into a single storage space. A spanned
array configuration must have the same number of disk drives in each basic
array. For example, a RAID 5 array containing three drives cannot be combined
with a RAID 5 array containing six drives.
RAID 10: Spanning with Mirrored Arrays
A RAID 10 configuration combines multiple RAID 1 arrays into a single storage
space. The data is mirrored within each RAID 1 array and striped across all the
RAID 1 arrays that constitute the RAID 10 logical drive. For example, if your
RAID 10 configuration spans two RAID 1 arrays, data blocks are written as
follows:
Stripe 1
Stripe 2
Stripe 3
RAID 10 Advantages
There is no data loss or system interruption due to disk failure, because if
one disk fails, its mirror image is available.
Read performance is fast, because data is available from either disk in each
pair.
RAID 10 lets you create large logical drives:
With the HP NetRAID-1M adapter, the total number of disks in the
RAID 10 logical drive is limited by the number of disks that can be
attached to a single SCSI channel. For example, if the Rack Storage/12
enclosure is used, the maximum number of disks in a RAID 10 logical
drive is 12.
With the HP NetRAID-2M adapter, you can span up to eight RAID 1
arrays, resulting in a 16-disk RAID 10 logical drive.
Spanned Array (RAID 10)
Array 1 (RAID 1)
Disk 1 Disk 2
Block 1 Block 1
Block 3 Block 3
Block 5 Block 5
RAID Overview
Array 2 (RAID 1)
Disk 3 Disk 4
Block 2 Block 2
Block 4 Block 4
Block 6 Block 6
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