On Wed, Mar 18, 2015 at 02:39:26PM -0700, K Richard Pixley wrote: > On 3/18/15 14:06 , Chris Murphy wrote: > >The Fedora/RHEL/CentOS installer creates two subvolumes: root and > >home. If you check out fstab, those subvolumes are mounted at / > >and /home. Therefore the top level subvolume (id 5) is not mounted > >by default, so there's no way to delete subvolumes in the top > >level. > Ah! Thank you. That's the piece I was missing. > > IMO, someone needs to take a clue-by-four to the heads of the > Fedora/RHEL/CentOS installer folks. I see no reason for this with > btrfs.
Actually, it's the recommended approach. We've found over time that nesting subvolumes inside each other is, in general, more trouble than it's worth. It makes it harder to do things like take snapshots and then replace the original with a snapshot (e.g. rollback to an earlier state). Arranging the subvolumes with the top level (subvolid=0) as nothing but a store for subvolumes means that you don't get the subvolumes tangled up with each other, so it's much easier to manage them in general. There's a few cases where nesting subvolumes is helpful, but that's more to do with preventing snapshots being taken of some pieces of the filesystem. Hugo. -- Hugo Mills | "There's a Martian war machine outside -- they want hugo@... carfax.org.uk | to talk to you about a cure for the common cold." http://carfax.org.uk/ | PGP: 65E74AC0 | Stephen Franklin, Babylon 5
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