James A. Peltier wrote: > Mounting a snapshot requires the generation of a new UUID for the file > system in order to be able to use it. Perhaps this is a XFS limitation, > but unlike ZFS they aren't immediately available. We need to perform this > action extensively to backup file systems and allow for quick data > recovery.
Another side effect of snapshots and using LVM for example(applies to any vendor's block based snapshots), is you can't easily take a snapshot of an LVM-based file system, then mount that snapshot on the same system, LVM will bitch. I spent some time trying to play with dynamically changing the UUID in the volume group but gave up, too complicated for my needs, instead I just mount the snapshot on another system(or a VM with either Raw device mapping in VMware or a software iSCSI initiator on the guest). I've written a few scripts for things like mysql snapshots and Oracle snapshots over the years with my 3PAR array, using SSH and key-based authentication the interface is pretty easy, a single command to create a read-only snapshot, then another command to create a read-write (read-write snapshots must be children of read-only ones in the 3PAR world anyways). The process takes less than a second, and if I want to snapshot a dozen volumes at the same instant, still a single command and the array ensures all volumes are taken at the same point in time, very helpful for Oracle snapshots which can get messy if your dealing with multiple volumes and not having them all perfectly in sync with each other. nate _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos