On Mon, Oct 17, 2016 at 11:49 AM, Michael Hamilton <michael@actrix.gen.nz> wrote:
I was looking to make an exact copy of a tumbleweed root btrfs filesystem on removable media. One aspect that makes this more fiddly is the number of subvolumes that are part of the root filesystem, including /opt and many sub-directories of /var.
Is there any technical document describing the reasons behind having so many subvolumes?
a) SUSE wants to use snapshots of system as safety measure. Snapshots are per-subvolume, you do not want to revert your database when you revert failed kernel update, so applications are placed in own subvolumes. What complicates things, /some/ parts of /var actually belong to the system as a whole (package database is the best example of it) so you cannot simply move whole /var to own subvolume. Probably in the long run filesystem hierarchy needs to be revisited. b) btrfs is not particularly friendly to some workloads like database or VM image. Again, storing such data in separate subvolume provides for disabling offending btrfs features (CoW in the first place) per-subvolume.
Someone else was asking the same question at stackexchange (with no real answers) :
http://unix.stackexchange.com/questions/285011/why-does-my-tumbleweed-opensu...
Is there a recommended way to get a faithful offline bootable backup of a btrfs rootfs?
snapper :)
Finally, I'm not determined to use btrfs. I'm moving up from 13.1. I'm evaluating Leap and Tumbleweed. It's a simple desktop, no RAID, one user. Would ext4 be a better choice?
Regards, Michael -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
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