On Fri Feb 06 2015 at 12:06:33 PM Brian B <canis8...@gmail.com> wrote: > > My laptop has two disks, a SSD and a traditional magnetic disk. I plan > to make a partition on the mag disk equal in size the SSD and set up > BTRFS RAID1. This I know how to do. > > The only reason I'm doing the RAID1 is for the self-healing. I realize > writing large amounts of data will be slower than the SSD alone, but > is it possible to set it up to only read from the magnetic drive if > there's an error reading from the SSD? > > In other words, is there a way to tell it to only read from the faster > disk? Is that even necessary? Is there a better way to accomplish > this?
What you may want to look at is lvmcache + btrfs. I've played with lvmcache (using ext4 on top) and btrfs independently, but not together. Too many new technologies at the same time for my taste. :) The best documentation I've found on lvm cache is the man page: http://man7.org/linux/man-pages/man7/lvmcache.7.html LVM cache uses dm-cache behind the scenes and makes it much more manageable (i.e. construction, manipulation, and teardown of devices. An lvm cache won't help with redundancy, the blocks will either exist on the caching device or slower device. To remove the cache, you can force a flush of the blocks out of the to the traditional HDD and use it without the cache without having to recreate the file system. -- 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
