[imp] Permformance issue

[Eric Rostetter]

Quoting tomc@teamics.com:
 
> My 2c:

And a very good "2c" it is!

> No web server or SQL server should be uniprocessor in a production setting.

Well, not exactly true.  Our departmental web server runs just fine on
a 266Mhz single CPU system with 128M of ram....  

Now, obviously we don't run Horde/IMP on that machine.  It actually does 
run php/cgi scripts though, not just static content.  Not one single 
complaint about performance.  Of course the load is very low.  I know a 
lot of small businesses that run production web servers which have hits 
in the tens (not hundreds, tens) per day and do very well with a
single cpu system (often off a DSL line).

Now, would I consider running a big site on such a machine?  No!  But if
you have a small site, with small load (number of hits) it works fine.

> We finally decided it was more cost effective to go with two machines, one
> which was a serious IO monster, the other which was a dual xeon with 4gb
> ram and etherchannel capable network cards.  Place a private 100baseT
> between the two machines, and good to go.  Backups run on the IMAP server.

We're heading in a similar direction on several large projects, except we
have yet to decide/do the private interface.  We simply etherchannel 4
100 full duplex lines, and run everything over them.  Can you give any 
performance (not security/reliability data) on the effect of having a 
private line between them rather than using the etherchanneled cards?
 
Feel free to reply off-list if you want. :)

> We also liked the split configuration because the performance/capacity
> calculations indicate that should we double the number of clients, we only
> need to add another web front end, because the incremental load on the imap
> server does not increase as rapidly as the http in relation to the number
> of active accounts.

We've also seen this for our non-Horde applications, and hence are moving
to this setup also.

> We watch the performance and latency on the link between the two machines,
> because that could present latency problems for imap.

I'd love to hear more about this.

> Certainly your mileage will vary, and there are probably hundreds of other
> 'correct' answers given the same inputs.

Yep.

> tc

-- 
Eric Rostetter
The Department of Physics
The University of Texas at Austin

"TAD (Technology Attachment Disorder) is an unshakable, impractical devotion
to a brand, platform, product line, or programming language. It's relatively
harmless among the rank and file, but when management is afflicted the damage
can be measured in dollars. It's also contagious -- someone with sufficient
political clout can infect an entire organization."

--"Enterprise Strategies" columnist Tom Yager.