Re: Mail clustering
--On March 20, 2007 4:37:25 PM +0100 Cherubini Enrico <email@example.com>
Tue, Mar 20, 2007 at 04:27:36PM +0100, Marek Podmaka wrote:
thanks for your reply.
First you should identify what is your bottleneck. Is it postfix? I
the bottleneck is the hardware, a dual xeon 3.20GHz with 2GB of ram, that,
is pretty high on load in the antivir/antispam server (of course).
I'd ascertain what kind of load. If it's I/O, NFS will likely make it
worse since NFS increases latency to disk by huge amounts. Also I've had
some serious issues with the 2.6 NFS server and have stayed on 2.4 for our
NFS server because of this.
A machine that size should be able to handle a LOT of scanning. 2Gb of ram
though is really anemic for high mail volumes with AV/AS. I'd suggest 4Gb
or 8Gb. Run vmstat and watch it, see if you're swapping, see how much
cache you're using.
RBLs). IMAP/POP3 can use some disk + CPU for sorting emails. But
usually the bottleneck is antivirus/antispam. So until you get disk
bottleneck I think one server for smtp + pop3/imap is enough and you
can use many servers for antivir/antispam. Which solution do you use?
Does it permit to define alternative hosts for antivir/antispam?
as for the a/a server, we use postfix+various dnsbl+amavis+clamav (postfix
patched for quota support), while the "standard" server is the same
without dnsbl and all antivirus things.
My idea is to use two servers, ie for the a/a, with round robin, to be
able to balance the load because I'm sure that in a few months even a more
powerful server reache the limit, without changing anything else in
customers configurations, dns zones, and so on.
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