Btrfs and upgrade paths

[mightyvoid]

Would I be correct in assuming that people wanting to use Btrfs in f16 will need to do a clean install?

[DBelton]

I would assume that changing the root filesystem would require a clean install rather than an upgrade.

Even if there is an upgrade option that would change the filesystem, I don't think I would trust it.

i think there is a way to switch to btrfs without doing a clean install .. let me try an find the howto

[mightyvoid]

Originally Posted by DBelton

I would assume that changing the root filesystem would require a clean install rather than an upgrade.

Even if there is an upgrade option that would change the filesystem, I don't think I would trust it.

It would be worth a shot, something of a curiosity, I'd definitely back up my data first.

---------- Post added at 12:59 PM ---------- Previous post was at 12:58 PM ----------

Originally Posted by detox

i think there is a way to switch to btrfs without doing a clean install .. let me try an find the howto

Interesting, i'd be keen to see what you find.

https://btrfs.wiki.kernel.org/index.php/Btrfs-convert

[DBelton]

the note on that page looks really promising, detox

Note: This program must be build seperately by "make convert" and might not work or even build.

I might give it a shot on one of my test boxes, though.... See what it does.

i do believe leigh123linux built it and worked fine, thats how i remembered the conversion tool

[DBelton]

well, if it doesn't work, I have an install DVD handy.

[jvillain]

I converted a few systems from ext4 to btrfs and they all worked except one. That one coughed up an error about half way through and and just quit the conversion. No data loss. I have tried the mount the ext4 partition roll back and that works as well.

[DBelton]

I have done some looking at how that conversion is actually done, and it looks like it there shouldn't be any data loss until you decide to make it final and remove the ext metadata.

What it looks like happens is that the conversion uses the same data locations and converts the metadata, writing the new metadata to freespace and keeping the old metadata as well. The actual data is never moved, and remains as is was before the conversion.

That means that until you actually commit and remove the ext metadata, you should be able to undo any of the conversion with no data loss.

[jvillain]

That's correct.

[milomak]

for those with space, shouldn't this work:

- copy the root partition to another space on your hard drive
- format the root partition to be btrfs
- copy the data back to the btrfs partition

I seem to remember doing the same thing when ext4 came out.

[mightyvoid]

All very useful information, thanks everyone. I may yet attempt a conversion, after doing an extensive backup to sdb, should it fail I'll be doing what milomak suggested.

[kellerman]

when I last time installed F15, i tried to format root partition as btrfs, but popup said that btrfs partifions cannot be bootable...

Originally Posted by kellerman

when I last time installed F15, i tried to format root partition as btrfs, but popup said that btrfs partifions cannot be bootable...

boot partition cannot be btrfs . it can only be in your root filesystem untill Grub2 is in Fedora it can be both