> -----Original Message----- > From: [email protected] [mailto:[email protected]] > On Behalf Of Dirk H. Schulz > Sent: Thursday, January 14, 2010 12:21 PM > To: linux clustering > Subject: [Linux-cluster] Snapshotting GFS and freezing > > Hi folks, > > I found several howtos on the web stating that if you want to snapshot a > gfs volume (on top of clvm, of course), you have to freeze gfs (using > gfs_tool) to make that possible. > > What comes in mind then is: If I have to freeze the gfs volume anyway, > do I need a snapshot at all? Can't I copy the contents off the frozen > gfs volume directly? > Because the basic purpose of a snapshot is to provide files that do not > change during beeing copied. And I would expect a frozen gfs volume to > provide exactly that.
The important consideration here is: How long can you withstand the filesystem being frozen? You can freeze it, copy all files (e.g. with rsync) and unfreeze, potentially over the course of a few hours. If that's okay with your application and users, go right ahead. Or you can freeze, snapshot and unfreeze, and potentially be done within a few seconds. That's the beauty of snapshots--we do it online with little or no user disruption. -Jeff -- Linux-cluster mailing list [email protected] https://www.redhat.com/mailman/listinfo/linux-cluster
