[CentOS] best disk configuration

Mon May 26 19:04:55 UTC 2008
Nikolay Ulyanitsky <lystor at lystor.org.ua>

On Mon, 2008-05-26 at 14:40 -0400, Mag Gam wrote:
> I have 12 750GB drive appliance from HP. I was wondering what is the
> best disk configuration? I suppose a large RAID5 would be bad since
> rebuilding would take too long. What do you recommend?

I prefer RAID10.
You can create 1 RAID-10 device with 12 * 750 Gb / 2 = 4.5 Tb size.

Also you can create 3 RAID-10 devices with 4 HDD per device. Each MD
device's size will be 3 * 750 / 2 = 1.125 Tb.

http://wiki.linuxquestions.org/wiki/RAID#RAID_10:_Striping_across_Mirror_sets :
"RAID 10 provides better performance than simple RAID 1 along with the
redundancy that simple RAID 0 lacks. It requires at least four drives to
implement and provides usable space equal to S*N/2 where 'S' is the size
of the smallest of the hard drives being used and 'N' is the number of
disks in the array. So, if I form a RAID 10 of four 10 GB disks, the
usable size of the array is 20 GB.

RAID 0+1 and RAID 10 are very similar but, by most measures of both
performance and redundancy, RAID 10 is considered to be preferable.

A RAID 10 can withstand the failure of a single drive (or multiple
drives, so long as they are NOT in the same mirror set)."

Nikolay Ulyanitsky <lystor at lystor.org.ua>