Problem with MySQL connection through load balancer

[Dean Goldhill]

Thanks very much.
That does clear up where I should be looking.

I will update if I find a solution.

Sent from my iPhone

> On 23 Jul 2014, at 17:39, "Phil Mayers" <p.mayers at imperial.ac.uk> wrote:
> 
>> On 23/07/14 17:10, Dean Goldhill wrote:
>> 
>> I have tried to use the ‘lifetime = 120’ option in the sql.conf
>> 
>> Under normal operation, this will cause radius to close and re-establish
>> the SQL connection every 120 seconds, so I hoped that when in this stuck
>> state, it would do the same and re-establish the connection. But does not.
> 
> The problem is, FreeRADIUS will be blocked inside the mysql libraries. So "lifetime" probably won't help.
> 
>> 
>> Is there anything someone can suggest?
>> 
>> I don’t have the ability to sync the session table between the 2 load
>> balancers.
> 
> The problem isn't FreeRADIUS - it's the mysql libraries. They're not detecting the dead connections.
> 
> Does the load balancer have the ability to return a TCP RST or ICMP error when it receives a packet for an unknown session? If so, this will probably trigger the mysql libraries to drop the connection, and FreeRADIUS to reconnect.
> 
> Otherwise, you'll need to investigate if MySQL has any form of dead connection detection, and how you can persuade your mysql libraries to do it.
> 
> TCP keepalives probably won't help - they're usually too slow for this kind of thing.
> 
> Alternatively, something like:
> 
> http://dev.mysql.com/downloads/mysql-proxy/
> 
> ...could be run locally. We use pgbouncer on postgres for this - it can check the connection is alive before sending a query and reconnect as needed.
> -
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