Re: PG HA solution using DBRD

Actually, if you are using DRBD as shared disk HA solution (am I correct or
you are using postgresql replication, like streaming and hot standby?),
then all the PG_DATA directory has to be on DRBD.
So, if you power off your 1st node and start your second (pointing the same
DRBD PG_DATA directory) it will continue from were the 1st node stopped (if
fsync was enabled, if not you may loose the last entries performed on
memory but not committed on disk). For this to happen you have to change
the data path of the second nodes postgresql script, found under
/etc/init.d/ to point to DRBD's $PG_DATA directory.

Hope I was helpful.

On Nov 10, 2010 9:52pm, Isabella Ghiurea <isabella(dot)ghiurea(at)nrc-cnrc(dot)gc(dot)ca>
wrote:

> Thanks for reply.

> DBRD cfg we have :primary/primary both of the servers can be used for
> writes/active while only one will be active always and other one is
> passive ( PG is offline)

> the user data directories and pg_xlog is using DBRD, the PG software
> directory and $PG_DATA is local on each server.

> Isabella

> tsoupl(at)gmail(dot)com wrote:

> Hi,

> What king of configuration do you have on DRBD? is it Primary/primary or
> Primary secondary?

> On Nov 10, 2010 12:12am, Isabella Ghiurea
> isabella(dot)ghiurea(at)nrc-cnrc(dot)gc(dot)ca> wrote:

> > Hi All,

> >

> > I 'm testing a HA solution for a PG version 9.01 database configured
> using DBRD for pg_xlog directory and user data /table space partitions.(
> block disk changes are copied from master to slave )

> >

> > the archive mode option is off for both master and slaver node, when I
> power off master without a clean PG shutdown the slave database server
> will not start. Bellow is the errror, what are my option to increase the
> checkpoint frequency ?

> >

> > archive_mode is off for both server

> >

> >

> >

> > database system was interrupted; last known up at 2010-11-09 08:27:02
> PST

> >

> > 2010-11-09 13:20:03 PST [8505]: [2-1] LOG: could not open
> file "pg_xlog/00000001000000BC00000006" (log file 188, segment 6): No
> such file or directory

> >

> > 2010-11-09 13:20:03 PST [8505]: [3-1] LOG: invalid primary checkpoint
> record

> >

> > 2010-11-09 13:20:03 PST [8505]: [4-1] LOG: could not open
> file "pg_xlog/00000001000000BC00000006" (log file 188, segment 6): No
> such file or directory

> >

> > 2010-11-09 13:20:03 PST [8505]: [5-1] LOG: invalid secondary checkpoint
> record

> >

> > 2010-11-09 13:20:03 PST [8505]: [6-1] PANIC: could not locate a valid
> checkpoint record

> >

> > 2010-11-09 13:20:03 PST [8499]: [2-1] LOG: startup process (PID 8505)
> was terminated by signal 6: Aborted

> >

> > 2010-11-09 13:20:03 PST [8499]: [3-1] LOG: aborting startup due to
> startup process failure

> >

> > postgres(at)proc5-15:errorlog$ >

> > Thank you

> >

> > Isabella

> >

> > >

> > --

> >

> > -----------------------------------------------------------

> >

> > Isabella A. Ghiurea

> >

> > Isabella(dot)Ghiurea(at)nrc-cnrc(dot)gc(dot)ca

> >

> > Canadian Astronomy Data Centre |
> http://www.nrc-cnrc.gc.ca/eng/services/hia/data-centre.html National
> Research Council of Canada, Herzberg Institute of Astrophysics 5071 West
> Saanich Road, Victoria BC V9E 2E7, Canada

> >

> > Phone: 250 363-3446 fax: 250 363-0045

> >

> >

> >

> >

> >

> > --

> >

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> >

> --

> -----------------------------------------------------------

> Isabella A. Ghiurea

> Isabella(dot)Ghiurea(at)nrc-cnrc(dot)gc(dot)ca

> Canadian Astronomy Data Centre |
> http://www.nrc-cnrc.gc.ca/eng/services/hia/data-centre.html National
> Research Council of Canada, Herzberg Institute of Astrophysics 5071 West
> Saanich Road, Victoria BC V9E 2E7, Canada

> Phone: 250 363-3446 fax: 250 363-0045