HP Integrity rx4640 Server - Manual (Page 85)

Drive Arrays and Fault Tolerance
HP Smart Array 5300 Controller User Guide D-11
HP CONFIDENTIAL
Writer: Kimberly Koch File Name: m-appd drive arrays and fault tolerance.doc
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Table D-2: Choosing a RAID Method
Most Important Also Important Suggested RAID Level
Fault tolerance Cost effectiveness RAID ADG
I/O performance RAID 1+0
Cost effectiveness Fault tolerance RAID ADG
I/O performance
RAID 5 (RAID 0 if fault
tolerance is not required)
I/O performance
Cost effectiveness
RAID 5 (RAID 0 if fault
tolerance is not required)
Fault tolerance RAID 1+0
Other Fault-Tolerance Options
Your operating system may also support software-based RAID or controller
duplexing.
•
•
Software-based RAID resembles hardware-based RAID, except that the
operating system works with logical drives as if they were physical drives. To
protect against data loss caused by physical drive failure, each logical drive must
be in a different array from the others.
Controller duplexing uses two identical controllers with independent, identical
sets of drives containing identical data. In the unlikely event of a controller
failure, the remaining controller and drives will service all requests.
However, the hardware-based RAID methods described in this appendix provide a
much more robust and controlled fault-tolerant environment. Additionally, controller
duplexing and software-based RAID do not support online spares, auto-reliability
monitoring, interim data recovery, or automatic data recovery.
If you decide to use one of these alternative fault-tolerance options, configure your
arrays with RAID 0 for maximum storage capacity and refer to your operating system
documentation for further implementation details.