RAID-5 and database servers

Eric Rostetter rostetter at mail.utexas.edu
Fri Mar 12 13:17:12 CST 2010


Quoting "John G. Heim" <jheim at math.wisc.edu>:

> We have mysql databases for spamassassin bayesian rules, hore3/imp web mail,
> and drupal. We also have a small departmental database updated via  my own
> web apps.

Drupal and horde are _probably_ going to be mostly read heavy, so they
probably don't matter.

You're going to have to concerns:

1) The SA bayesian rules might be very write heavy, if you get a lot of
    mail, and depending on if you do autowhitelist or other such things,
    and how often you expire them, etc.
2) You have concurrent DB access (multiple databases), so we need to know
    how many hits each gets...

Since your mail user base is small, the horde DB isn't really an issue.
So we need to know how much drupal is hit, and how many SA hits it will
take...

My guess is, that will only about 200 users, raid-5 would be fine.  But
I'd take that back if you are doing something like SA auto-whitelisting
also...  Or if for some reason your drupal site is very well visited...

The biggest trap, as I see it, is if you say "this is fine because we only
have 200 users" and then a couple years down the line you've somehow grown
to 1000 or 2000 users instead...  If you plan to stay small, then I'd say
raid-5 would probably be fine.  If you forecast growth, then maybe not.

The other trap would be what happens if you get "spam bombed" and get say
a couple million spams sent to you in an hour or so... Do you expect to
survive this without slowdown, or is it okay that it slows down until the
spam bomb dies down?  You might only get a spam bomb like this once every
5 years, but if it does happen, what are your expectations?  (Here spam
bomb could also be a joe-job, a virus outbreak, or other unexpected mail
event... Pick your favorite...)

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

Go Longhorns!



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