What happens when perlbal reverse proxy backend server dies?

Todd Lipcon todd at amiestreet.com
Thu Aug 30 20:22:34 UTC 2007

Hi Can,

Try adding the following to your reverse_proxy:

   SET verify_backend =  on

Hope that helps


On Thu, 30 Aug 2007, Can Sar wrote:

> Hi,
> I have perlbal set up as a reverse proxy to load balance between two 
> instances of Apache. When one of the machines is taken offline/dies/etc. it 
> seems that Perlbal becomes far slower at answering even a single request (no 
> other load on the slower), and that load time goes from 1 second to 6 seconds 
> or so. It seems to me that it tries to connect to the machine, eventually 
> times out and then goes to the other machine but never marks the machine as 
> down or anything else. Is this the expected behavior?
> I would ideally like it to detect that the machine is down, not give requests 
> to it and then eventually probe if the machine is back up after a few minutes 
> or so. I guess having to manually re-add the machine after failure would also 
> be ok.
> I've tried to find documentation on the managment interface but haven't had 
> any luck and the help command only lists commands without explaining their 
> syntax...
> Here's my config file:
> CREATE POOL apache
> SET nodefile = /etc/perlbal/nodelist.dat
> SET listen =
> SET role = reverse_proxy
> SET pool = apache
> SET persist_backend = on
> SET persist_client = on
> ENABLE dynamic
> Thanks!
> Can Sar

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