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Could you please elaborate? Maybe explain a tiny bit what brtfs subvolumes are.
It's definitely possible to preserve "normal" disk partitions with Anaconda.
Fedora 17 released
Posted May 30, 2012 14:09 UTC (Wed) by drag (subscriber, #31333)
Btrfs allows you to pool storage volumes together in a manner similar to LVM.
Although, I believe, it operates at a logical data/file system layer rather then block layer like LVM does. This allows you to do fancy things like stripe your metadata using a 'RAID10' and make your data 'RAID1'. Another distinct advantage to this is that your volumes don't have to match sizes or be of even numbers. So I can create a 'RAID1' array of a 500GB disk drive with a 1TB disk drive and a third 2TB disk drive. The file system just logically makes sure that any hunk of data is available on at least two devices. Newer versions of Btrfs allow you to rebalance and restripe your volumes on the fly in addition to being able to remove and add storage devices whenever you feel like it.
Btrfs allows you to break up your pool into separate file systems. Each with their own metadata and other such things in their own namespace. These divisions are called 'subvolumes'. By using subvolumes you can take easier advantage of features like snapshotting, different mount options, quotas, and the like.
If you look at the 'root' btrfs volume then subvolumes will show up as things that are like "/.subvolname". Although you can individually mount them and access them without first mounting the root subvolume.
So on my 'home system' which I use to house many KVM guests in addition to being my main desktop system I have, IIRC, 3 1TB drives combined with 2 2TB drives in a BTRFS storage pool.
The various file systems that I use shows up on the btrfs root volume as:
The initrd for Fedora is sufficiently btrfs-aware that I can specify that it use a subvolume to be mounted as '/' for my OS during boot up.
Now the problem with Anaconda that I have ran into the past is that is unless it's able to support the file systems I am using that I cannot seem to be able to use it to install or upgrade Fedora.
I would like it if I could just tell Anaconda to skip the whole disk formatting and mounting BS and just use something like /mount/target/ and let me figure out how to setup the file systems after it's done it's install. If I could do that then that would be the preferred method for upgrading my OS as I can use a live CD to setup the volumes how I want it and then just use Anaconda from there.
I haven't really looked into it too deeply right now and as far as I know the 'target' option may exist. I just am not that familiar with it. I haven't had time to download the Fedora 17 installer and play around with it since my original post.
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