[Mimedefang] Performance parameters

[Steve Moore]

I am trying to plan for MD/SA deployment here.  I would like to get the 
benefit of experienced MD/SA users' concerning performance.  Our site 
processes up to 500,000 messages daily.  Our average message size is 
30KB.  Our max mail message size is 100MB.  We have two AIX 5.1 machines 
running commercial sendmail behind a Cisco local director for load 
balancing.  One AIX machine is a dual processor with 4GB of memory and it 
has cpu and i/o wait below 30%.  The other machine is a uniprocessor with 
1GB of memory and it also has cpu and i/o wait below 30%.  Both machines 
have separate spindles for /var/spool.  We do not do AV on these 
machines.  That is accomplished at another layer.  Our plan is to tag and 
pass all mail along to the client. The only content analysis we are 
interested in at the moment is spam probability.

My questions are as follows.
1) Is it possible to process the current workload with the two machines 
listed above once MD/SA is added to the mix?

2) Should I expect a 20% scan time improvement by adding RAMdisk?

How would you rank the performance cost of each of the checks below?  How 
would you rank the benefit of each of the checks in calculating spam 
probability?

1) SA rbl checks.
2) SA Bayesian analysis.
3) SA Razor checks.
4) SA dns availability.

I know I am asking for a lot but hopefully others can benefit from your 
wisdom.  Thanks in advance for any comments.


Steve Moore
Senior Software Coordinator
Miami University
113 B Hoyt Hall
Oxford, OH 45056
email:mooresm at muohio.edu
voice:513-529-1452
fax:513-529-9665