Miserable performance of cyrus-imapd 2.3.9 -- seems to be lockingissues

Vincent Fox vbfox at ucdavis.edu
Wed Mar 5 14:07:21 EST 2008


David Lang wrote:
>
> raid 6 allows you to loose any two disks and keep going.
>
>   

This is turning into a RAID discussion.

The orginal poster was doing a RAID-5 across 3 disks, and has stopped
commenting but it's probably because that's all the hardware he could 
scrounge.

I am a staunch member of BAARF however and don't trust
RAID-5/6 for a New York second. See
http://www.baarf.com/

We do ZFS RAID-10 across LUNs provided from arrays on a SAN
through multipathing.  Within the arrays the LUNs are RAID-5.
Belt AND Suspenders.

Your mere RAID-6 doesn't pass my standards for reliability and
high availability, because there can still be errors along the path
that are not caught until too late.  I can take a hammer to multiple
pieces of equipment without downtime.

But we are a datacenter with 50K+ users who get very cranky when mail
is down for any amount of time at all.  I've worked in smaller departments
and different standards apply there.  YMMV.

Once you go ZFS you'll never go back, it's like the first time you had a
journalled filesystem and thought ah some relief from worries over 
corruption!





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