Re: [AMaViS-user] high wait I/O when amavisd-new turned on

[Luc de L. <luc...@bi...>]

Muenz, Michael wrote:
> Hi list,
> 
> I've replaced my old mailserver with a quadcore xeon,
> 4gb RAM and LSILOGIC SAS Raid. With this step I switched bayes
> from DB_File to MySQL.
> Switchover was easygoing, and the CPU usage is 4 times
> lower with the new machine, but I can see a huge increase
> with iowait and the normal system load. When working on 3 mails
> at the same time %wa in top raises up to 30%!!! Shutting down amavisd-new
> reduce it to 0 - 4. I've checked everything:
> - amavis in ramdisk
> - bayes with db_file again
> - bayes with innodb or myisam
> - bayes completely off
> - turned off RBLs
> 
> Nothing leads me to success. I have a second MX set up
> exactly the same, great performance, but with one difference:
> The second MX uses software raid. With the new one, debian
> detects the raid so ne need to build one. I thought that
> would speed up things, but it seems to be the opposite.
> 
> Any ideas how to track down the error (without reinstall
> with SW raid :)

Hi Michael,

Run a file system benchmark such as bonnie to see what is the raw 
throughput of your file system. I do not think that this issue is a 
amavisd-new issue.

Please also consider using MySQL's caching facilities to optimize read 
performance from the DB and watch it carefully.

Thanks,

Luc