Thanks Fajar for quick response!

Now I know there exists mutual influence among virtual servers.

Oddly, instead of seeing the error message " There are no DB handles to use ", there are bulk of "Discarding duplicate request from NMS - ID xx due to unfinished request xxxx", then after about short period of time, it showed msg "WARNING: Unresponsive child for request xxxx, in component authorized module", can I still say that is due to problematic DB?

> > That is, even virtual server ?A? only has few operation to check,

> > while ?B? has much more things need to check and unfortunately maybe

> > it could have low performance DB backend, does B might occupy

> > resource in whole Authorize section so that A also become more and more busier?

> >

> > **

> >

>

> Yes

>

>

> >  **

> >

> > In fact, I got many times of Error msg ?child is hung for request in

> > component authorize module? in radius.log. I would not think the

> > loading in our server was really much high enough for causing late

> > response to simulated request from our NMS per **minute**. Our wifi

> > auth request per day is among 2000~3000 in average.

> >

>

> only 2k per day? That's tiny. Something if seriously wrong with your

> db if it can't handle that much requests.

>

> IIRC one way to isolate problematic db is to use small num_sql_socks

> in sql.conf (default is 5). If the db is slow, it should bomb out

> quickly with "There are no DB handles to use" errors, but there should

> be only a small count of FR threads interacting with that db so that

> processes not using it (e.g. other virtual server) should still work just fine.

>

> --

> Fajar