Avago Technologies MegaRAID SATA 150-4 (523) - Manual (Page 36)

2-14 Introduction to RAID
Copyright © 2003–2006 by LSI Logic Corporation. All rights reserved.
RAID 5 uses disk striping and parity data across all drives
(distributed parity) to provide high data throughput, especially for small
random access.
RAID 10, a combination of RAID 0 and RAID 1, consists of striped data
across mirrored spans. It provides high data throughput and complete
data redundancy, but uses a larger number of spans.
RAID 50, a combination of RAID 0 and RAID 5, uses distributed parity
and disk striping and works best with data that requires high reliability,
high request rates, high data transfers, and medium-to-large capacity.
LSI does not recommend having RAID 0 and RAID 5 logical drives in the
same physical array. If a drive in the physical array has to be rebuilt, the
RAID 0 logical drive causes a failure during the rebuild.
2.5.2 Selecting a RAID Level
To ensure the best performance, you should select the optimal RAID
level when you create a system drive. The optimal RAID level for your
disk array depends on a number of factors:
•
Number of physical drives in the disk array
•
Capacity of the physical drives in the array
•
Need for data redundancy
•
Disk performance requirements
2.5.2.1 RAID 0
RAID 0 provides disk striping across all drives in the RAID array. RAID 0
does not provide any data redundancy, but does offer the best
performance of any RAID level. RAID 0 breaks up data into smaller
blocks and then writes a block to each drive in the array. The size of each
block is determined by the stripe size parameter, set during the creation
of the RAID set. RAID 0 offers high bandwidth.
Note: RAID level 0 is not fault-tolerant. If a drive in a RAID 0 array
fails, the whole logical drive (all physical drives associated
with the logical drive) fails.