On Fri, Oct 24, 2014 at 12:07 PM, Zygo Blaxell <ce3g8...@umail.furryterror.org> wrote: > > We could also leave this as an option to the user "mount -o > degraded-and-I-want-to-lose-my-data", but in my opinion the use > case is very, very exceptional.
Well, it is only exceptional if you never shut down during a conversion to raid1 as far as I understand it. :) > > IMHO the use case is common any time restoring the entire filesystem > from backups is inconvenient. That covers a *lot* of users. I never > have a machine with more than 50% of its raw disk space devoted to btrfs > because I need raw space on the disk to do mkfs+rsync from the broken > read-only btrfs filesystems. The problem is that if you want btrfs raid1 and you ALSO want to have an extra set of spares for copying your entire RAID1 to something else, you're talking about a lot of extra disk space. I really don't want to maintain a SAN just in case I have a btrfs problem. :) I realize things are still somewhat experimental now, but we need to at least think about how things will work long-term. Copying all your data to another filesystem and re-creating the btrfs filesystem isn't really a good recovery mode. Restoring from backups is also becoming increasingly difficult. IO bandwidth just has not kept pace with disk capacity. It can take the better part of a day to copy a multi-TB array, and if you need to copy it two ways you have to double the time, not to mention having multiple TB of disks lying around. -- Rich -- 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
