I'm sure many will answer the questions, so for a different perspective: Make sure you buy a drives from a number of manufacturers, or get ones from different production batches - I was once on a customer's site where two 'brand-x' drives in a RAID 5 array went bad within minutes of each other due to a spindle bearing defect and this took down the array.
 
-----Original Message-----
From: centos-bounces@centos.org [mailto:centos-bounces@centos.org] On Behalf Of Andrew Vong
Sent: 25 July 2005 10:57
To: centos@centos.org
Subject: [CentOS] RAID 5 vs. RAID 10


Hi,

I am looking into purchasing a new server. This server will be mission-critical.

I have read and somewhat understood the theories behind RAIDs 0, 1, 5, 10 & JBOD. However, I would like to get some feedback from those who have experience in implementing and recovering from a HDD failure using RAID.

Hardware specs include:-

Dual Xeon 3.2 GHz
2 GB RAM

I would like to implement hardware RAID but am unsure as to which would be most suitable for my needs. Any advice is appreciated.

Option 1 - RAID 5 (3 hdd's) + 1 hot spare

Option 2 - RAID 10 (4 hdd's) + 1 "cold" spare (in the shelf)


Questions I have :-

1) When should RAID 5 be implemented?
2) When should RAID 10 be implemented?
3) Is RAID 5 with a hot spare safer than RAID 10 with a "cold" spare?
4) Is it possible to configure RAID 10 to have a hot spare?
5) Should one of the HDDs fail, a hot spare w kick-in immediately and begin rebuilding. As I am planning to put in 300 GB HDDs, how long would this take on a RAID 5 vs. RAID 10?
6) Will there be a degradation in performance for users on the system (RAID 5 vs. RAID 10)?
7) What are the disadvantages of using RAID 5 vs. RAID 10?

Thanks in advance for answering my questions.

Best Regards,
Andrew