On Thu, May 22, 2008 at 7:12 PM, Guy Boisvert <boisvert.guy@xxxxxxxxxxxx> wrote:
> You do not need two (2) raid controllers unless you want to have
> redundancy at the controller level. Adaptec, 3Ware, etc do RAID 50.
> For RAID 50, you need at least 6 disks.
>
> http://en.wikipedia.org/wiki/RAID
>
>
> For database, i'd go with RAID 10. As pointed out Joseph in a previous
> post, RAID 5 rebuilding would slows the array down.
>
> As for RAID 10, i didn't make extensive benchmarks but here are the
> rough results i got with Adaptec 3405 and four (4) Seagate 15K SAS drives:
>
>
> RAID 5: Read = 170 MiB/s
> Write = 135 MiB/s
>
> RAID 10: Read = 170 MiB/s
> Write = 160 MiB/s
And stick with md-raid 10 (also known as software raid) because it is
much more intelligently designed than any
closed-source-embedded-raid-controller.
Nowadays hardware raid frightens me because of the need to have spare
raid-controllers for every hardware-raid-configuration I have. They
are neither interchangable nor easily recoverable.
md-raid 10 can be established with any number of disks (at least 3 but
better check with google)
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