Let's say A and B are running together. Then someone does a large update query and A is done with, while B is in the middle of it, and A crashes.
You can switch over to B, which won't contain the data, but it'll have a good snapshot of what the data was before the crash. When you recover the A machine, ( if you recover it.. ) and restart, B will catch up from where A left off. Remember, however, that if you update B while A is down, A won't have that data. ( Which is what I think you're asking about? ) This is like any backup solution or when you are replicating anywhere for redundancy. You can only backup so much before a crash happens. When you do crash, then you at least have a good starting point of data. If you're asking about an actual recovery process.. Let's say B becomes the master machine for awhile. When the A machine is recovered, you take a snapshot of B's data and put it over on A. Then start A and have it slave to B and it will catch up from that point. If you want actual instructions, just think of creating A as a new slave to B. Follow the instructions in the mysql docs about creating a slave. -- sh On Thu, 2002-03-28 at 14:54, Joe Bifano wrote: > I am trying to configure mysql for redundancy using replication and the > built-in mysql master/slave configuration. What I don't understand, even > after much reading, is how to recover from a failure. If host B is slave to > host A, and A goes down, B could then be manually or automatically > configured to be master itself, and thus take over A's role completely. > However, if B was not completely caught up from A before the failure took > place, then once A was back up the two would be out of sync, and A could > contain data B did not, and B would undoubtedly contain data A did not. How > do you avoid this situation or re-sync the two after a failure like this? > > I'm finding it difficult to locate a concise and cohesive method to create a > redundant database system using mysql. Any other resources or references > would be heartily appreciated. > > Joe > > --------------------------------------------------------------------- > Before posting, please check: > http://www.mysql.com/manual.php (the manual) > http://lists.mysql.com/ (the list archive) > > To request this thread, e-mail <[EMAIL PROTECTED]> > To unsubscribe, e-mail <[EMAIL PROTECTED]> > Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php > --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
