Re: Configurations for performance

On Fri, 2007-03-30 at 11:56 +1000, Jake Anderson wrote:
> > When I first installed my test systems I had MySQL
in master-master
> > replication which worked great, but my bubble was
burst with the IMAP
> > ID not being guaranteed to be incrementing for
each message. I found
> > that the traffic on the network using the built-in
replication was
> > about 20% of the traffic on the network using drbd
(plus writes should
> > be faster)
> >
> I'd run multi-master and then use a perdition setup on
each machine such
> that users only access one machine for their email. As
all reads/writes
> for one user happen on one machine you should avoid
that problem.
> If you have a failure then all users get pointed to the
one machine and
> everything keeps going.

Perdition would solve the IMAP UID problem, but it doesn't
help with the
plain old auto_increment collisions...

If we combined Perdition with per-server auto_increment id
windows, then
I think we'd be onto something!

Aaron

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Aaron Stone wrote:
> Perdition would solve the IMAP UID problem, but it
doesn't help with the
> plain old auto_increment collisions...
>
> If we combined Perdition with per-server auto_increment
id windows, then
> I think we'd be onto something!
>   

So you don't think you need to have smtp delivered to the
particular 
server? What if an email is delivered at the same time an
email is 
copied into the folder? I realise this is probably rare but
it will happen.

If that's not a problem, does anyone have a working example
of failing 
over the perdition config in the case of a server failure?

That said I'm still looking at the possibility of using
Postgres and 
MySQL to split the dbmail / dspam databases up... I'll get a
setup 
eventually 
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> Perdition would solve the IMAP UID problem, but it
doesn't help with the
> plain old auto_increment collisions...
>
>   
Yeah thats what i was thinking, to me thats just part of
multi master
replication.

Although... you wouldn't really need multi-master as each
server really
is the "real deal" with all reads and writes being
done on it. The
backup will only be used if the master is gone. It might
still be an
idea to set it with the auto_increment value (in mysql at
least, i don't
know about postgres), just incase you get a "split
brain" situation.
> If we combined Perdition with per-server auto_increment
id windows, then
> I think we'd be onto something!
>
> Aaron
Thats what i was thinking.
postfix can direct mail to a host based on a database
lookup.

so LDAP or something probably, a script that synchs your
smtp servers
worst case.
smtp should probably be behind ultramonkey to provide a
"seamless"
interface there too. But for outbound it doesn't really
matter much if
your servers drop.
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