Thank you for your detailed information about HA and LB. First of all it's a pitty that there is no built-in feature for LB+HA (both of them, simultaneous). In my eyes, the pgpool2/3-solution has to much disadvantages and restrictions. My idea was the one, that john described: DML and DDL are done on the small box and reporting on the "big mama" with streaming replication and hot stand-by enabled. the only problem is that we use temp tables for reporting purposes. i hope that the query duration impact with not using temp tables will be equalized through running dml/ddl on the small box.
I think, this will be the final configuration: - drbd with multi primary (ocfs2) as archive location for the primary node - streaming replication and hot stand-by this is a good howto to get real high availability when the primary node goes down, but for now I'm going to deploy the described configuration with manual fail over. http://www.howtoforge.com/how-to-set-up-an-active-passive-postgresql-cluster-with-pacemaker-corosync-and-drbd-centos-5.5 Regards, Jasmin 2011/2/27 Andrew Sullivan <a...@crankycanuck.ca> > On Sun, Feb 27, 2011 at 12:10:36PM -0800, John R Pierce wrote: > > are made to the master server, but reads are done to either. note you > > do NOT want to use block level replication like drbd for this as the > > drbd slave can not be actively mounted, nor could the slave instance of > > postgres be aware of changes to the underlying storage, rather you would > > use the streaming replication built into postgresql 9.0. > > Note that with drbd, you can have a piece of hot standby hardware > sitting there to take over the filesystem in real time, in the event > the original master blows up or something. My experience with systems > designed like this is that they are a foot-bazooka: the only real > utility I ever saw in them was to increase on-call hours for sysadmins > after they blew off their own foot (and too often, my database) doing > something tricky with the standby server. If it were me setting it > up, I'd think the streaming replication approach a better bet. Not > that anything will save you when someone else has root and decides to > play with a production server. > > I believe that Greenplum sells a system based on Postgres that is > supposed to do some kind of distributed cluster thing. I don't > understand the details and it's been a long time since I had any look > at it. I think it's intended to compete in the scalability rather > than the availability market. Maybe someone around here knows more. > > The only people I'm aware of who really do this sort of thing for > availability are Oracle with RAC, and Oracle with some mostly-works > clustering stuff in MySQL. I have never met a happy customer of the > former, but I've heard some people tell me it's real impressive > technology when it's working. (The unhappy people seemed mostly > unhappy because, for that kind of coin, they would like it to work > most of the time. I know at least one metronet deployment that didn't > work even once for two years.) In the case of the MySQL stuff, there > are some trade-offs in the design that make my heart sink. But maybe > for the OP's application it will work. > > A > > > -- > Andrew Sullivan > a...@crankycanuck.ca > > -- > Sent via pgsql-general mailing list (pgsql-general@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general >
