This is veering a bit OT, hence the top-post, but it looks like another HA
option may be available in a few months:
http://lists.freebsd.org/pipermail/freebsd-announce/2009-October/001279.html
In short, you can stack any geom-aware FS on top of this. Combined with
CARP, you've got a decent/simple/cheap option.
Pawel does really good work, I look forward to playing around with this.
Charles
___
Charles Sprickman
NetEng/SysAdmin
Bway.net - New York's Best Internet - www.bway.net
sp...@bway.net - 212.655.9344
On Thu, 22 Oct 2009, Steve wrote:
-------- Original-Nachricht --------
Datum: Thu, 22 Oct 2009 12:57:56 +0100
Von: Ed W <li...@wildgooses.com>
An: Dovecot Mailing List <dovecot@dovecot.org>
Betreff: Re: [Dovecot] HA Dovecot Config?
Steve wrote:
Hallo Ed,
I have never used FileReplicationPro but looking at what it offers it
reminds me of GlusterFS. I use GlusterFS for all www data of the domains I
host. I don't use jet GlusterFS for IMAP/POP storage for all domains I host.
Only a small subset of the domains I host have GlusterFS for IMAP/POP but
so far it works without issues and I will soon or later migrate the other
domains to be on GlusterFS as well.
The setup of GlusterFS is ultra easy (compared to other clustering FS
solution I have seen) and it offers some very nice functions.
In the past I have burned my fingers with older GlusterFS releases when
I have tried to use it as storage for IMAP/POP but the later 2.0.x releases
of GlusterFS are more stable.
The thread moved on and no one seemed to bite, but I also have watched
glusterfs for a long while now and been very attracted by the basic
principle. I would be very interested to hear more about how it's worked
out for you?
I use GlusterFS since long time. For mail hosting I waited for release 2 and
then when it was out I switched all mail domains to use GlusterFS 2.0.1. It was
a ultra big failure for me. The process took so much CPU that I could barely
run anything else on the system and stability was very, very bad. That forced
me to switch back to NFS for all the domains. Then later around 2.0.4 I looked
again at it and things where more stable. I started then with a bunch of
domains to run on top of GlusterFS 2.0.4 and moved then to GlusterFS GIT and
somewhere around 2.0.7 the GIT version broke horribly in my setup that I
switched to 2.0.7. That has been some weeks ago and since then I run around 1/3
of my domains on top of GlusterFS 2.0.7 with two active nodes using server side
replicate, io-threads, write-behind and io-cache. On the client side I have no
performance translators or anything such. Just bare client. I used server side
replication because I wanted the shared storage to behav
e
like a SAN and not use the server part as dumb bricks where the client is
responsible for the replication. So far both nodes have 2 x 1TB disks in RAID 1
mode and those disks are then exported as a GlusterFS brick doing replicate.
Setup in Dovecot is +/- like you would do if you would use NFS.
Got any benchmarks, perhaps comparing against local
storage and vs NFS?
I have benchmarked but have nothing made to show to others. In general I can
say that using GlusterFS on gigabit network is +/- 1/3 to 1/2 of the raw disk
speed. If you add performance translators then the speed is somewhere between
1/2 to 1/1 of raw disk speed (depending what block size I use and depending if
I use Booster or not). With the performance translators you can easy saturate a
gigabit connection. Have not tried to use anything faster then gigabit.
Off course local storage is faster since I don't have that theoretical 125MB/s
limit I have when using gigabit. The newer releases of GlusterFS are comparable
to NFS in terms of speed. In terms of CPU usage GlusterFS is way behind NFS and
local storage. In terms of flexibility GlusterFS is better then anything else.
It seems intuitively very appealing to use something heavily distributed
in the style of gluster/mogile for the file data, and something fast
(like local storage) for the indexes. Perhaps even dovecot proxying
could be used to help force users onto a persistent server to avoid
re-creating index data...
Have never tried MoglieFS. What I don't like about it is that it uses HTTP for
transport and operations.
For smaller setups it would be appealing to find something simpler than
DRBD for a two server active/active setup (eg both servers acting as
both storage & imap and failover for each other)
That is easy done with GlusterFS. Very easy.
Cheers
Ed W
// Steve
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