Domas Mituzas wrote: > Hi! > >> Don't be so eager. >> >> Replication will break in funny ways when a 5.1 master will get a v5 >> event. > > ??? what do you mean?
...if it has v4 slaves >> In the best scenario, all mysql4 slaves stop replicating at once, >> overloading the 5.1 ones and leading the wiki to a halt. > > We can run the site off a single slave, usually (well, probably need to send > watchlists to blackhole for a while, but.. ;-) > >> Domas ends up >> removing the offending statement with a hex editor or upgrading all the >> slaves in a hurry. > > Who in the sane mind upgrades masters before slaves? Perhaps someone that wants to be able to switch the master back to a mysql4. Was that a wild idea that if there's no 'upgraded to mysql 5.1' entry in the log, the old mysql4 master was kept as a slave? Note that I wasn't assuming a setup with the master being the only mysql 5.1, just that still were _some_ v4 slaves. werna has already cleared up that all slaves are also 5.1 so all is good. >> Do we have at least one 5.1 slave per 5.1-mastered pool ? > > Did we have ever any non-5.1 slave per 5.1-mastered pool? > > Domas When answering, I looked at wikitech but was unable to find the mysql version each slave was running. Consider it a bug #1 issue :) Aryeh wrote: > You can't replicate from lower versions to higher versions, in > general. Only the reverse is safe. So if the master is 5.1, we can > assume all the slaves are probably (at least) 5.1. mysql replicates the sql statements, so I wouldn't be surprised if a mysql5 which only received mysql4 compatible statements worked as master for mysql4s. _______________________________________________ Wikitech-l mailing list [email protected] https://lists.wikimedia.org/mailman/listinfo/wikitech-l
