Crap Nullpointer Exceptions
This is the blog of John Dulaney, a hacker of Fedora, SCAdian, player of Music, blacksmith, sailor, and consumer of Bacon.
Mucking about with btrfs
Today I changed one of my partitions over to btrfs (1)(2). At first I had trouble getting mkfs to work, but then it was pointed out to me that the tools to actually do btrfs are not installed by default unless the filesystem is selected at install time (thanks fenrus02 for pointing out what should have been obvious, DOH!).
So far, I’ve had no issues and I have dumped a good 11 GB on it.
For those that are interested, the (very easy) steps are as follows (/dev/sda3 was the partition I used):
- su – (easier to just do this since there are several steps that require root permission)
- yum install btrfs-progs
- umount /dev/sda3
- mkfs -t btrfs /dev/sda3
- blkid to get the new uuid for the drive
- edit /etc/fstab to automatically mount where I wanted it (include the new uuid and, in my case, replace ext4 with btrfs)
- mount /dev/sda3 /home/jdulaney/Media
- You may need to edit the permissions for Media (or whatever mount point you go with)
- You’re done!
So far, I’ve had zero errors, and I’ll probably start converting the rest of my file system shortly.
(1) https://fedoraproject.org/wiki/Features/F16BtrfsDefaultFs
(2)https://btrfs.wiki.kernel.org/index.php/Main_Page
Crap Nullpointer Exceptions 
Nice! I’ll probably migrate my laptop over to Btrfs sooner rather than later, too.
I’d still not recommend people to move over to btrfs yet, not until it gets some sort of fsck which is able to fix problems. I was using btrfs since a few releases, but a few months back my installation got completely borked because of a forced poweroff using power button. The partition was completely unusable and btrfsck was unable to do anything about it. There was no way to retrieve any data from it. Luckily it was a rawhide partition and so i did not lose much, but this made me wary of switching to btrfs in my F15 install.
In short: Keep btrfs for testing on non-essential partitions only until btrfsck is able to handle errors
Good points Most of my data (and all essential data) is on an ext4 partition. I also do regular backups, so I’m not worried about losing data. If / gets too mommicked, I can just do a reinstall.
Of course, my perspective here is that as I’m QA, I will continue using experimental stuff.
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