> When I first installed my test systems I had MySQL in master-master > replication which worked great, but my bubble was burst with the IMAP > ID not being guaranteed to be incrementing for each message. I found > that the traffic on the network using the built-in replication was > about 20% of the traffic on the network using drbd (plus writes should > be faster) > I'd run multi-master and then use a perdition setup on each machine such that users only access one machine for their email. As all reads/writes for one user happen on one machine you should avoid that problem. If you have a failure then all users get pointed to the one machine and everything keeps going.
You should get more performance and the same redundancy. If you have 3 machines then you can have your data backed up twice, and all the performance of 3 frontends and use mysql's own handling of recovering from network breaks. If you got fancier you might be able to setup some kind of system where each user was on 2 machines (but not 3) for an added performance boost at the cost of some redundancy. hmm you would need to split your users into 3 parts and have 6 databases/frontends but it should work machines = A,B,C users into groups of a,b,c machine A has a + b, B has b + c , C has c + a. set each user group up on one database install and then replicate that db to one other machine. use heartbeat or something to script what happens when a node goes offline. it'd be more work but should give you the best use of your hardware. If your feeling keen do all your setup inside Xen then you can migrate a node transparently. > The reason to try drbd is that it looked fairly easy to fail over and > back, but now that I think of it a split-brain situation is going to > cause data loss no matter which way it's resolved. I'll have to do > some research on failing over MySQL and Postgres master-slave > configurations. > > Regards, > Josh. > _______________________________________________ > DBmail mailing list > [email protected] > https://mailman.fastxs.nl/mailman/listinfo/dbmail _______________________________________________ DBmail mailing list [email protected] https://mailman.fastxs.nl/mailman/listinfo/dbmail
