> I am aware of that not all kernel hackers like such configurations, and
> that some will rather see small RAID-configurations connected with VLM.
> I beleive there is a reason for using RAID-6, and RAID-controller vendors
> (such as Compaq) are already using them, so why shouldn't linux do so
> also? With a high number of cheap IDE drives, the chance of one failing is
> quite high, so why not RAID-6? At least for a system doing most reads...
See the following thread from March 2002 on linux-raid:
http://groups.google.com/groups?hl=en&lr=&safe=off&th=804941541a023c63&seekm=linux.raid.Pine.LNX.4.44.0203261239110.12942-100000
You can always fake this effect by combining two 8-disk RAID-5s into a
RAID-0. It's not technically RAID-6, but can withstand a 2-disk failure,
although not _any_ 2-disk failure. However, it's my understanding that
RAID-6 cannot withstand _any_ two disk failure either (see the above
thread).
I also suspect that the use of dual RAID-5s combined with the CPU overhead
of ATA will kill most systems under any kind of load. For that matter, the
2x parity hit from RAID-6 probably wouldn't make you CPU too happy either,
even if there was a kernel driver that implemented it.
--- Derek Vadala, derek@cynicism.com, http://www.cynicism.com/~derek
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