Upgrading to ubuntu 15.10 magically improved things. It's possible it was running fsck, or something.
I would like to close this as fixed. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1460447 Title: Boot slow, "scanning for btrfs filesystems" takes 100 seconds To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1460447/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
