Red Hat Bugzilla – Bug 1017159
Cannot use BTRFS partition as root when already used
Last modified: 2013-10-09 13:55:13 EDT
Description of problem:
When using a large BTRFS partition for multiple "virtual" partitions, Fedora cannot be installed to a subvolume (the installer does not give the option).
Every time, once set up.
Steps to Reproduce:
1. Install Ubuntu with BTRFS (I have it under dm-crypt as well)
2. Add subvolumes (in my case, one for "data", one for "gentoo", one for "fedora". Ubuntu made "@home" and "@". "@" was renamed to "@ubuntu"
3. Attempt to install Fedora on the same BTRFS partition.
Installer wanted a "clean" root partition -- which is what the "fedora" subvolume was for.
Ability to select a subvolume for Fedora which is empty, or create a new subvolume for fedora when the root partition is BTRFS.
I do have Gentoo and Ubuntu on the same BTRFS partition -- the boot partitions are separate, so it should not be a limitation.
You should be able to create a new subvolume in your existing btrfs filesystem to install fedora to.
You'll want to use custom partitioning (review/modify/&c). Create a new btrfs device with mountpoint '/'. If necessary, select your existing btrfs filesystem/volume from the dropdown menu on the lower-left of the "configure mountpoint" area.
"Empty" or "fresh" filesystems that already exist are not supported for use as the root filesystem, but a new subvolume that we create is acceptable.
I figured it out (I was trying to specify a subvolume for the root filesystem, and was expecting the installer to do something like the following:
subvolume delete [name] ; subvolume create [name]
instead of using Fedora's defaults, in order to avoid naming conflicts). I'll do what I did with Ubuntu, but it isn't always clear that "adding" a partition with BTRFS partitions will add a subvolume instead of wiping the entire partition.
Closing as NOTABUG. Because it isn't a bug.
Yeah, you're right -- it can be a bit of a guessing game as far as what exactly will happen behind the scenes. In general, though, we won't ever remove/destroy devices without you asking us to do so -- that's the worst kind of surprise. Thanks for the report.