On Thu, 2008-01-31 at 10:02 -0500, Chander Ganesan wrote: > Magnus Hagander wrote: > > On Thu, Jan 31, 2008 at 03:34:05PM +0100, Martijn van Oosterhout wrote: > > > >> On Thu, Jan 31, 2008 at 01:28:48PM +0000, Simon Riggs wrote: > >> > >>> That sentence has no place in any discussion about "backup" because the > >>> risk is not just a few transactions, it is a corrupt and inconsistent > >>> database from which both old and new data would be inaccessible. > >>> > >> Hmm? I thought the whole point of a filesystem snapshot was that it's > >> the same as if the system crashed. And I was fairly sure we could > >> recover from that... > >> > > > > That was my assumption as well. *Assuming* that the filesystem snapshot is > > consistent. There are a bunch of solutions that don't do consistent > > snapshots between different partitions, so if your WAL or one tablespace is > > on a different partition, you'll get corruption anyway... (seen this in > > Big Commercial Database, so that's not a pg problem) > > > Agreed. That's why I made it a point to mention that all of your > tablespaces should be on the same file system... In hindsight, I should > have also stated that your WAL logs should be on the same file system as > well... I think we all understand and agree, I just start twitching when anyone talks about it being OK to lose transactions when backing up. You meant the ones currently in progress, not the ones already committed and on disk. -- Simon Riggs 2ndQuadrant http://www.2ndQuadrant.com ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
