On Thu, 06 Aug 2015 07:18:08 -0400, Rich Freeman wrote: > I'll skip the bits that were already dealt with. > > On Thu, Aug 6, 2015 at 5:19 AM, Peter Humphrey <[email protected]> wrote: >> >> First, btrfs balance. I had no idea that was needed, so of course I didn't >> include it in my attempts. Could that be why, on booting, the kernel couldn't >> mount the file system? > > It isn't necessarily essential, but btrfs fi df /mnt/gentoo will show > you that before the balance there are still some chunks in single mode > - it seems like mkfs creates the first device and adds the second one, > leaving some residual non-RAID chunks (that hopefully will never have > data written to them). The balance of an empty filesystem is really > fast and completely converts it to raid1, so I figured it would be > cleaner to do it this way. I have no idea what happens if those > single chunks remain and you degrade the array.
Btw this should be fixed in btrfs-progs 4.1.3, hopefully out soon. I have the necessary patch in my local overlay and no longer see leftover single chunks after mkfs. -h
