Desperately trying to debug poor spam scanning performance

[Jason Ede]

You could try looking at the RAID performance...

first with just

hdparm -t /dev/sda

Then try changing blocksize by using

blockdev --setra 0 /dev/sda

and trying values of say 0,1,2,4,16,32,64,128,256 (default CentOS one I believe), 512, 1024,2048

Should be able to produce a table of read/write performance on each system... Be interesting to compare the values of the 2 servers.

Jason





________________________________________
From: mailscanner-bounces at lists.mailscanner.info [mailscanner-bounces at lists.mailscanner.info] On Behalf Of Glenn Steen [glenn.steen at gmail.com]
Sent: 16 September 2008 13:49
To: MailScanner discussion
Subject: Re: Desperately trying to debug poor spam scanning performance

2008/9/16 Ben Tisdall <ben.tisdall at photobox.com>:
> Steve Freegard wrote:
>
(snip)
>>
>> 4)  Have you mounted /var/spool/MailScanner/incoming on tmpfs?
>
> On this box not really an option, can't upgrade the RAM beyond 2G & it
> has to perform duties other than MS :(
>
> I'm strongly tending towards the theory that I/O is crappy on this box.
> I read something not very complimentary about the smart array 5/i on
> Linux & certainly the bonnie++ results are worse than those for my home
> box (2 x 15K SCSI on the test box, 2 x 7.2K SATA at home).

Sorry for not noticing this earlier:/.
Smart 5i with write memory cache "addon" is "somewhat OK", the default
el cheapo 5i you find onboard is usually not worth using. They will
suck eggs through straws, when it comes to write performance.
Get a real RAID card, not the memory thing... better value for money.
Smarts are generally OK, so long as you stay away from the really
_too_ cheap thingies:-).

> In all likelihood I'll now be given a new box for MS with enough RAM to
> do incoming on tmpfs :)

New box == better RAID controller;-).
My latest is a HP DL360G5 ... Actually with a very basic setup (==low
price). Good value for money AFAICS. The E200i seems to perform OK:-).

> Thanks for your suggestions Steve.
>
> Best regards,
>
> Ben.
>

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