On 11/11/2015 07:32 AM, Edward Ned Harvey (blu) wrote: >> From: Discuss [mailto:[email protected]] On >> Behalf Of Chuck Anderson >> >> According to Ted Ts'o (filesystem developer), it is NOT a recommended >> way to backup your filesystem: >> >> http://www.gossamer-threads.com/lists/linux/kernel/1197768 >> >> "It does read the mounted block device directly, and so it's certainly >> not a _recommended_ way to back up your ext4 filesystem. It should > > That's correct, but unfortunately, it doesn't leave you with anything else > you can use. The problem is that the live filesystem can have stuff changing > while the operation is in progress. Because you're not using a block-level > snapshot. So even if you use something like rsync or rsnapshot, the tool will > walk the live filesystem (on top of the filesystem layer, unlike dump which > operates below the filesystem layer, but that distinction is irrelevant) the > filesystem could be changing while in the middle of an rsync operation. Or > tar, or cpio, or whatever. Your database files are not safe with *any* of > these tools, because of no block-level snapshot. > > If you make a block level snapshot, for example with lvm, you could then > safely backup the snapshot block device, just as you could safely mount the > snapshot and run rsync. But god, lvm snapshot, what a nightmare. > > This is the reason ZFS was invented. Maybe btrfs will be good someday too > (maybe it already is).
I would recommend against btrfs. This is the first filesystem I've used in two decades where a power failure caused corruption. Chris _______________________________________________ Discuss mailing list [email protected] http://lists.blu.org/mailman/listinfo/discuss
