Mailserver mem usage (OT)

[Glenn Steen]

On 11/04/06, Jørgen Giversen <jgg at giversen.net> wrote:
> Dear all I have just setup a new mailserver (the old hardware was
> getting unstable)
>
> Harware:
> Intel 7320 motherboard
> 1 Xeon 2.8
> 1Gb ram
> Adaptec29320 Scsi controler
> some SCSI disks
>
> software:
> OS: Centos 4.3 I386 (not X86_64)
> Mailscanner 4.52.1
> SA 3.11/pyzor/razor/dcc
> ClamAV, BDC
> Mailwatch 1.0.3
>
> It scans around 1500 mails a day in total (also taking care of some
> other internet services )
> I works fine but something bothers me.
>
> The old system had about 600 mb ram when i looked at "top" it always
> showed that it used all the mem available. The new system however shows
> that it uses about 300 mb with about 700 mb free. Can anybody tell my
> why it is not using all the mem that's available?
>
> --
> This message has been scanned for viruses and
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> believed to be clean.
>
One can think of several reasons:-).
On the "old" system, you probably had most of your memory "tied" to
filesystem caching etc, that is to say in "readily returnable
state"... So if the kernel policy for how much of the memory is
used/allowed for such differ, you will see a marked difference there.
Also, this caching can take some time to "build up" so if the system
hasn't been running for more than a (rather) short while, it might not
have had time to amass any significant use (if you use slocate or
similar, thoat/those cron-jobs usually "fill this up" eventually:-).

Unless you see some (real) performance issues, this shouldn't be
anything to worry that much about.

--
-- Glenn
email: glenn < dot > steen < at > gmail < dot > com
work: glenn < dot > steen < at > ap1 < dot > se