SQLIPPool performance issue

[Peter Nixon]

On Thu 26 Jul 2007, Alan DeKok wrote:
> Roy Walker wrote:
> > Ok chaning the indexes definately made some difference.  The database
> > load still went off the charts, but the radius logs were much better
> > with DB errors connect errors.  This still seems horribly slow.
>
>   The problem is that RADIUS servers take less time to do things than an
> SQL server needs.  So when you hammer the RADIUS server with requests,
> the SQL server is getting 5-10x the load.
>
> > Here is the command I am using to test: /radclient -p 2 -d
> > /usr/src/freeradius-server-snapshot-20070725/share -f
> > /tmp/radclient-test 1.1.1.10 auth testing123 Where the radclient-test
> > file has 5000 client requests seperated by the necessary blank lines.
>
>   FreeRADIUS should really be a little smarter about loading the SQL
> server.  But it's a very hard problem to solve in a good way.
>
>   i.e. "if SQL server is busy, stop processing the current request, BUT
> remember to wake up later to keep processing it."
>
>   The only real solution is to get a bigger machine to handle the
> database, OR slow down on the RADIUS traffic.

Yep. there are a few things you can do to limit disastrous situations though.
* Turn off any SQL query that you don't need...
* Run Accounting and Auth queries through different sql module instances so a 
flood of auth doesn't kill accounting and visa versa. SQLIPPool can be on a 
3rd instance...
* Give the radippool table a dedicated disk spindle, or even a dedicated 
server..
* Likewise for radacct vs all the auth tables.. Auth is read intensive, acct 
is write intensive.. (You can use different types of RAID even...)
* Use radrelay for accounting if possible. Queueing is good for your health..

Given that as far as I can tell you are ONLY testing Auth performance at 
present, most of these wont help you :-(

Cheers

-- 

Peter Nixon
http://peternixon.net/