RAID Performance Questions

Milo Hyson milo at
Thu Jan 25 21:19:39 UTC 2007

On Jan 25, 2007, at 12:15, Chuck Swiger wrote:

> Still, you also ought to consider that a 3-disk RAID-5  
> configuration is very much not ideal from either an efficiency or  
> performance standpoint-- you want more like 5 or 6 drives being  
> used, in which case your performance numbers ought to increase  
> some.  This is also somewhat true of the 4-disk RAID-10 config;  
> using 6 or all 8 drives would likely improve performance compared  
> with striping against only two disks.

Unfortunately, I'm a bit limited in terms of equipment and  
application requirements. For starters, the app specs currently call  
for two arrays: one for general file-serving and databases, and the  
other for backups. Due to limited hardware I'm to run both on the  
same controller. Far from ideal, I know, but it's what I have.  
Second, I need to keep at least one drive as a hot-spare. Thus, I  
have seven drives that I somehow need to partition into two groups  
and maximize performance without sacrificing reliability. Lastly, the  
RAID controller does not permit more than two drives in a RAID-1 set.

Any suggestions?

Milo Hyson
CyberLife Labs

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