On 30-10-14 14:23, Rogerio Pereira wrote:
>  
>>>Do you have anything that checks if your services are alive? If so:
>>> is it just a "connection open" test or a "proper" imap test ?
>  
> Yes,  I have.  HostMonitor is installed in my Android Phone and queries
> the imap, pop ports every 2 minutes to see if it’s alive. It’s a not
> “proper” imap test. It’s just a “connection open” test as you mentioned.

Every 2 minutes should not be a problem, if you have a login_timeout=60
or lower.

> I am monitoring the production server because of the DBmail stability
> issues. Service uptime is a huge deal for me right now.

Normally, if you kill an existing connection (RST) this is detected by
the network layer and the connection is cleaned up. Sometimes however,
if dbmail doesn't receive the RST packet, the connection will have to
timeout. If you are using a monitoring app that doesn't send a RST to
terminate a TCP session, I wonder if the app is not the problem.

I've worked quite a bit on this last year, and the only way I could test
and reproduce this behaviour was by setting up firewall rules that would
drop RST packets.

>  
> I am monitoring the “opened files” by dbmail imapd process and I can see
> it grows steadily every minute (ls -l /proc/<pid>/fd | wc –l). I changed
> the “open files” limit to 4096 in the server. It may fix the imapd
> issue, but it does not fix the pop3d issues. Pop3d hangs every day with
> “general protection” errors.
>  
> dbmail01 kernel: [21981989.961192] dbmail-pop3d[9821] general protection
> ip:7f92daba880a sp:7fff2cb2ae38 error:0 in
> libdbmail.so.0.0.0[7f92dab64000+6b000]
>  
> Is Pop3d failure related to this monitoring as well?

If you find out, please let me know! But I don't think so.

> What changes in dbmail.conf could fix this “connection leak”  created by
> monitoring?

Try setting a lower login_timeout in dbmail.conf


-- 
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Paul J Stevens       pjstevns @ gmail, twitter, github, linkedin
           www.nfg.nl/i...@nfg.nl/+31.85.877.99.97
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