I work at a company where we have a cluster of 4 machines with PG and Slony-I. These 4 machines are split in two data
centers, so we have one ´master´ and one ´slave´ on each data center, and then one of the masters is the slave of the other: DC1 DC2 Master --> Master | | V V Slave Slave Our setup ensures that writes to the DB (which are done only a few times a day by big batches with) are only done on THE master (in the graph, the master in DC1). I have three questions about this setup: What happens if THE master dies? We can stop the batches that inject the data, but will the slaves hold the reads (several thousand a day) while we re-establish THE master? And what exactly happens when THE master is back up and we restart the batches? What if a slave is out for a day (for instance, HW testing)? Can we just read it to the cluster? The current internal procedure involves dropping the node, dropping the slony schema, rebuilding the node and resuscribing the replication lines, which includes a full data copy. Which would be a good way to invert the relationship between the masters? The internal procedure involves stopping the batches, changing the subscriptions and restarting the batches (during the night, when the activity is low). _______________________________________________ Slony1-general mailing list [email protected] http://lists.slony.info/mailman/listinfo/slony1-general
