On 10/14/2016 01:38 PM, Austin S. Hemmelgarn wrote: > On 2016-10-13 17:21, Alberto Bursi wrote: >> Hi, I'm using OpenSUSE on a btrfs volume spanning 2 disks (set as raid1 >> for both metadata and data), no separate /home partition. >> ----- >> I'd like to be able to clone verbatim the whole volume to another >> volume, for backup purposes. >> >> Now, I think I can do that with a brutal partition clone from my >> "recovery" (a debian system installed in another drive) and then doing >> the procedures to deal with a lost drive. >> >> But I'd rather prefer a clone on a live system, and without doing a >> brutal clone as that will keep the same UUIDs. >> >> I can(will) script this so even if it is a tedious process or it >> involves writing a huge line in the commandline it's not an issue. > I'm not sure there is any way to do this on a live system. You > essentially need to either do a block level copy and change the UUID's > (which recent versions of btrfstune can do), or use send with some > manual setup to get the subvolumes across. Both options require the > filesystem to be effectively read-only, which is not something that any > modern Linux distro can reliably handle for more than a few minutes. > > If I had to do this, I'd go with the block level copy, since it requires > a lot less effort, just make sure to use btrfstune to change the UUID's > when the copy is done (that may take a while itself though, since it has > to rewrite a lot of metadata).
Heh, one of the reasons I migrated to btrfs was that I wanted to do things like these on a live system. With my script I can already generate any necessary folder structure and send over all subvolumes with a bunch of btrfs send | btrfs receive with like 5 lines of script. I was hoping there was some neat trick with btrfs send | btrfs receive that allowed me to send a snapshot of / to the / of the new volume. With rsync (from a ro snapshot of /) it should be possible to use the subvolume list as exclusion list, but I'd have rather wanted to use a btrfs feature instead. -Alberto
