> In a nutshell: organize your heterogenous disks into two "halves", the sum of > which are of roughly equal size, and create a raid1 array across those two > halves. > [snip] > > In the long term, I would like this to be something that btrfs could do by > itself, without LVM. Having absolutely no knowledge of the btrfs code, this > seems easy, I'm sure you'll tell me otherwise. ;) But one needs:
It already does this, no organisation necessary. > While btrfs seems to support multi-disk devices, in trying this, I encountered > the following deadly error: creating a raid1 btrfs with more than 2 devices > cannot be mounted in degraded mode if one or more are missing. (In the above > plan, a filesystem should be mountable as long as one "half" is intact) With > 1 > of 4 devices missing in such a circumstance, I get: I suspect you didn't make a raid1, but rather a raid1 metadata with raid0 data. > Both these errors were encountered with Ubuntu 11.10 (linux 3.0.9). I tried > with 3.0.22 and I got "failed to read chunk tree" instead of the above "failed > to read chunk root" and furthermore after mounting it degraded, I could not > mount it non-degraded, even after a balance and a fsck. 3.0 is seriously out of date: anything prior to 3.2 can cause problems on a hard reboot, and a bunch of other things have also been fixed. > P.S. why doesn't df work with btrfs raid1? Why is 'btrfs fi df' necessary? df works fine, but doesn't (and can't) give a complete picture: there's no way for btrfs to extend the syscall df uses to return more information without breaking the api for everybody else. Note that the faq covers all of these points :p -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
