Master-slave mysql redundancy

[Daniele Mantovani]

Hi to all,

I've setup two servers with freeradius 3, to have a redundant setup.
On the first server there a mysql master instance, and on the second server
there's the slave instance.
I'm using sql in radius to do some check, with the sql xlat, and to do some
accounting.

My goal is to find a setup for the second server, that would use the local
slave instance to do read-only operation (like the sql xlat query), and the
master instance to write the accounting data.

My initial idea was to use two sql instance in the setup, and use the right
one in the various places, but reading around I've found some information
about rml_sql_log and radsqlrelay, and I want to understand if it's a
better option in my case.

So I'm looking at the man pages but I haven't understand how to setup
radsqlrelay:
-Does I need to start the radsqlrelay command as a daemon? I haven't seen
any start script, or a way to make freeradius start that for me...
-Does I need to setup the rlm_sql_log module + radsqlrelay on all the
servers?
Or only on the slave server, to communicate with the database?
-Does the two radsqlrelay instance need to communicate eachother?

Thanks to all
Best regards

-- 
Daniele Mantovani
Opere Sociale don Bosco - Salesiani Sesto san Giovanni
02 26 292 397