Hi Jed, > If you are using LVM, you might consider snapshotting, however, doing a live > snapshot without stopping mysql server would only work if you were copying > only myisam tables. Mysql-hot-copy would probably be better, but either way, > you need to flush your tables, which will briefly lock them, so they can get > onto disk. > > In contrast, InnoDB actually needs to "shut down" to cleanly close its table > structures before you can physically copy the filesystem.
Actually, not true -- an LVM snapshot (or other snapshot) is a great way to take a backup of InnoDB. You just need a truly atomic snapshot, and then you can let InnoDB run its recovery routine on the snapshot to get back to a consistent state. > Why do I leave it firewalled? Because once you start writing to an LVM > volume that's been snapshotted, you start copying disk extents like mad, > creating a high load condition that can force queries to reach > connect_timeout. I have my connect_timeout set pretty low in my > environment. That will depend a lot on the workload. Here are some good links for further reading: http://www.mysqlperformanceblog.com/2006/08/21/using-lvm-for-mysql-backup-and-replication-setup/ http://www.mysqlperformanceblog.com/2008/06/09/estimating-undo-space-needed-for-lvm-snapshot/ -- Baron Schwartz, Director of Consulting, Percona Inc. Our Blog: http://www.mysqlperformanceblog.com/ Our Services: http://www.percona.com/services.html -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
