From: Sebastian Hagedorn (no email)
Date: Fri Jan 06 2006 - 08:17:18 EST
Hi,
--On 6. Januar 2006 12:47:49 +0100 Paul Dekkers <>
wrote:
> We are about to move our mail to a different machine, running a
> different OS and a different filesystem (ext3, since that is "the one"
> for RH).
that's why we use it as well. We started with XFS, but then Red Hat
wouldn't give us support. Anyway, with RHEL 3 we are quite happy with the
performance.
> While thinking about this filesystem for use with cyrus, I was
> wondering if it would do any good to split up the current mailspool in
> different imap partitions. I'm curious what others would do. I've
> searched the archive a bit, but for now it seems people are only
> partitioning for expanding storage...
>
> Currently there are about 7000000 files, split over 14000 mailfolders,
> consuming 250 gigabyes, for about 80 users.
Wow, that's a lot of mail for so few users! We have 40,000 users and 266
gigabytes of mail ...
> (Large part of it is a
> shared archive, a few have large user boxes.) Everything is on one
> partition now.
> Does it (filesystem / safety / recovery / performance-wise) make sense
> to use different partitions, maybe about 100G large, and spread archive
> and users over 3 or 4 partitions, or would you people rather put
> everything in a single partition instead? I have about 1 terabyte
> available (managed with lvm).
I've thought about that as well, but have decided against it. Having to
juggle partitions increases the complexity. The only real downside to large
partitions is disaster recovery and we feel we have that covered. Our SAN
is capable of "flash copies" and according to estimations we can recover
within about two hours. Hasn't yet been tested, though ;-)
> I think about not enabling dir_index on ext3 after discovering that this
> dramatically _decreases_ read-performance, so in that perspective this
> might keep the filesystem tables more clean and keeps down
> fragmentation? But if someone tells me that this really doesn't matter
> then I can as well keep everything in one partition: I don't see myself
> as a filesystem expert ;-)
Neither am I. We mount "-o noatime", that's it.
> P.S. Initially I want to make filesystem-snapshots and rsync the data to
> a different mailserver as sort of "hot standby". (Snapshots might be
> interesting for partitioning.) Later on we'll be using 2.3 and the
> replication code, after we did some more testing with that. But then
> we'd drop the redhat package too, and with that the support from redhat
> - I assume?
We don't use Red Hat's RPM, but the Invoca one. We never needed support for
Cyrus, only for OS related things.
> Does anyone have experience with the redhat support on
> cyrus? (Is it worth running 2.2 for instead of 2.3? ;-))
I don't think so. IMO the support is spotty at best, anyway. I really doubt
it will be much better for Cyrus.
Cheers, Sebastian
-- Sebastian Hagedorn - RZKR-R1 (Gebäude 52), Zimmer 18 Zentrum für angewandte Informatik - Universitätsweiter Service RRZK Universität zu Köln / Cologne University - Tel. +49-221-478-5587 Skype: shagedorn
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