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Subject: Re: high capacity configuration nightmares
From: Pere Camps (pereulivatar.com)
Date: Fri Oct 27 2000 - 10:02:53 CDT


Wietse,

> > machine: dual pentium III, 733 Mhz, .5 GB RAM, compaq smart
> > array RAID 5 controller.
> >
> > maximum smtp connections in postfix: 300
> >
> > sessions time
> > -------- ----
> > 50 2m10s
> > 100 1m39s
> > 150 1m20s

        I've just found out that I had been fooled in the compaq smart
array controller that we we're using (I didn't build the box).

        Today, I installed the smart array controller with 64 MB write
cache. The results are:

        sessions time
        -------- ----
        50 0m17s
        100 0m21s
        150 0m18s

        As you see, much better now.

        This all in sync mode. I do not bother to check on async.
Performance is fine by all accounts now. (I've ran the same tests but with
50000 emails and the performance was the same).

        I'm also still using RAID 5. We didn't have enough hardware to
test other types of RAID, and as we are going live next wednesday I want
the machine to cool off for some days.

        When I get my hands on some more hardware I will definetively try
it out on RAID 1.

        I will also look closer at the meta-updates and Linux async. I
don't know what meda-updates are and I'm concerned that they can wrong "on
their own". Power failure in our enviorment is very low risk (dual
power supplies, dual ups, dual diesel generators).

        Regards,

-- p.