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Re: Documentation of big "mail systems"?

On Fri, 15 Oct 2004 20:08, Paul Dwerryhouse <paul@dwerryhouse.com.au> wrote:
> On Fri, Oct 15, 2004 at 06:56:21PM +1000, Russell Coker wrote:
> > The machines were all running 2.4.2x last time I was there, but they
> > may be moving to 2.6.x now.
> All the stores, relays and proxies are still on 2.4.x, but the LDAP
> servers are now on 2.6.x (mainly because I could, not for any technical
> reason. At the time I upgraded them I had enough redundancy to go around
> that the downtime didn't affect anything).

In that case you should get the 4/4 kernel patch, it will make a huge 
improvement to your LDAP rebuild times which can come in handy in an 
emergency.  From memory I had the slave machines rebuilding in about 15 
minutes, I expect that I could get it down to 5 minutes with a 4/4 kernel, 
and less if the machine has 6G of RAM or more.

For 4/4 the easiest thing to do is probably to get the Fedora kernel.

> Four perdition/apache/imp servers now, rather than three. The webmail is
> rather popular now, and three servers couldn't cut it on their own
> anymore.

Is there any way to optimise PHP for speed?  Maybe PHP5 is worth trying?

> Seven backend mailstores now, and I really want an eighth, but can't get
> anyone to pay for it.

I still think that using a umem device for journals is the right thing to do.  
You should be able to double performance by putting a umem device in each 
machine.  It'll cost less than half as much as a new server to put a umem 
device in each machine, and give much more performance.

I recall that none of those machines was even close to running out of disk 
space.  You could probably handle the current load with 4 back-end machines 
if you used umem devices.

http://www.coker.com.au/selinux/   My NSA Security Enhanced Linux packages
http://www.coker.com.au/bonnie++/  Bonnie++ hard drive benchmark
http://www.coker.com.au/postal/    Postal SMTP/POP benchmark
http://www.coker.com.au/~russell/  My home page

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