Data integrity and RAID

I'm looking for a software solution to help replace my existing raid hardware
setup. The hardware mimics RAID-1 (in that it has 3 mirrors), except for the
fact that on read all 3 mirrors are compared and possibly error corrected
before data is returned. I don't neccessarily need a RAID-1 solution, it
just seems closer to what I already have and also that it also can recover
from 2 simulateous disk failures.

So far I've played with a software RAID-1 array of USB flash drives. My
issue is that software RAID-1 does not check for or recover from data
corruption unless a read or write to disk actually fails. Integrity is a
major concern for me, I need to know that all data going to and from disk is
correct at all times.

All advice and comments are welcomed.
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Re: Data integrity and RAID

At the moment, I would recommend using two drives in a raid1, and
rsync to the third. Then use some scripts with sha1sum to compare
between the raid and the rsync'd copy, which would effectively be a
backup copy. You could use a fuse filesystem called chironfs
http://www.furquim.org/chironfs/ to 'mirror' at the file level, and
sha1 or diff to compare all the disks at some regular interval.
chiron reads from the primary disk by default, and writes out to all
disks. I don't know of anything that reads all, compares, tiebreaks,
and repairs on each file access. I suspect that would perform quite
badly.

On Tue, Dec 9, 2008 at 07:55, peter.stevens wrote:
>
> I'm looking for a software solution to help replace my existing raid hardware
> setup. The hardware mimics RAID-1 (in that it has 3 mirrors), except for the
> fact that on read all 3 mirrors are compared and possibly error corrected
> before data is returned. I don't neccessarily need a RAID-1 solution, it
> just seems closer to what I already have and also that it also can recover
> from 2 simulateous disk failures.
>
> So far I've played with a software RAID-1 array of USB flash drives. My
> issue is that software RAID-1 does not check for or recover from data
> corruption unless a read or write to disk actually fails. Integrity is a
> major concern for me, I need to know that all data going to and from disk is
> correct at all times.
>
> All advice and comments are welcomed.
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