Production servers num_sql_socks

[Kenneth Marshall]

On Thu, Mar 05, 2009 at 09:19:19AM -0600, Ben Wiechman wrote:
> We set num_sql_socks to 25. We had them set to 10 but ran into issues when
> massive numbers of subscribers were attempting to enter the network at once
> - for example when we would power cycle a base station with 400 subscribers
> on it for maintenance. 
> 
> Ben Wiechman
> 
> 
> 
>  
> 
> From: freeradius-users-bounces+ben=wisper-wireless.com at lists.freeradius.org
> [mailto:freeradius-users-bounces+ben=wisper-wireless.com at lists.freeradius.or
> g] On Behalf Of Stelio Gouveia
> Sent: Thursday, March 05, 2009 8:55 AM
> To: freeradius-users at lists.freeradius.org
> Subject: Production servers num_sql_socks
> 
>  
> 
> I've read a few posts about increasing this value when " There are no DB
> handles to use" occur. Not sure if it's a good idea.
> 
> Granted your DB is fast enough to query quickly.
> Upping this value on a slow DB will severely degrade performance.
> 
> What's sort of values are you guys using for production servers?
> 
> -- 
> Regards
> Stelio Gouveia

The value depends on three inter-dependent factors:

1. the time to answer a query by your DB backend
2. how many queries can be handled reasonably by your backend
3. your request rate

Typically, there is a sweet spot, performance-wise for this
setting. If your backends are not available when needed, you
will have people unable to connect. If you increase the number
above which your backend DB can safely handle, you will have
a total service outage in a high load situation. A load test
with your setup is the best option. Good luck.

Cheers,
Ken