[pgpool-general: 4294] Re: Pgpool watchdog 3.4

[Yugo Nagata]

Hi Derek,

Although watchdog in pgpool-II 3.4 doesn't communicate after reconnecting
as Usama said, trusted_servers is one of the paramters to avoid split-brain.

If this is specified, watchdog tries to ping to these servers, and when this
fails, the local pgpool-II is regarded as down, so this can't become active
or standby until restarted.

http://www.pgpool.net/docs/latest/pgpool-en.html#TRUSTED_SERVERS


On Tue, 5 Jan 2016 17:24:27 +0500
Muhammad Usama <m.usama at gmail.com> wrote:

> Hi Derek
> 
> Unfortunately the watchdog in pgpool-II 3.4 and older version does not
> handle the network isolation and split-brain situations very well.
> Currently we are in the process of overhauling the watchdog for pgpool-II
> 3.5 which is in the beta at the moment and is planned to be released
> sometime this month. The new enhanced watchdog for pgpool-II 3.5 has
> addressed this and other watchdog related issues and hopefully will provide
> a better experience and more features.
> 
> Thanks
> Best regards
> Muhammad Usama
> 
> On Tue, Jan 5, 2016 at 11:33 AM, Derek <derek_kouch at yahoo.com.au> wrote:
> >
> > Hi,
> >
> > I've got a split brain question. Sorry for the long email.
> >
> > If the master pgpool server is disconnected from the network but is still
> running, when it reconnects after 10 minutes or longer, the master pgpool
> server's watchdog is still thinks it is still the master and it thinks the
> other pgpool server is down. However, it has lost the virtual ip to a new
> master. So when the new master is down, the old master does not get the
> virtual ip back because it still thinks it is already the master. In the
> end, the virtual ip is down.
> >
> > Does the watchdog communicate with each other after reconnecting to the
> network after a long absence?
> >
> > Is there a setting that I need to set to get the watchdogs to talk to
> each and to resolve who is the true master and who should get control of
> the virtual ip?
> >
> >
> > Kind regards,
> > Derek.
> > _______________________________________________
> > pgpool-general mailing list
> > pgpool-general at pgpool.net
> > http://www.pgpool.net/mailman/listinfo/pgpool-general


-- 
Yugo Nagata <nagata at sraoss.co.jp>