>>> "Scott Marlowe" <scott.marlowe@xxxxxxxxx> wrote: > Andreas Philipp <andreas.philipp@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote: >> We are wondering about the advisability to distribute the databases between >> the two server machines, both machines acting as active production systems >> for one application each, and as warm standby servers for the other, using >> WAL shipping to a second database cluster running on another port on each of >> the two server machines. >> >> What would be the performance cost of doing so, rather than running all >> databases on one database cluster on one machine, and using the second >> machine as a warm standby server for all databases of the two applications? > > Well, when both machines are working, your performance would be better > on two machines than on one. But after a failover, the warm standby > will be running two instances of postgresql, and that's sub-optimal. We have many machines here running multiple PostgreSQL clusters, including one running two clusters, each with hundreds of GB of data, which run tens of millions of queries per day without performance problems. (It's also running several Java processes through which all this traffic passes.) It is a matter of having adequate hardware, properly tuned databases, efficient software design, and well written queries. -Kevin
