On Fri, Feb 22, 2013 at 12:08:32PM -0500, Derek Atkins wrote: > Rich Pieri <richard.pi...@gmail.com> writes: > > > On Fri, 22 Feb 2013 11:29:42 -0500 > > Jerry Feldman <g...@blu.org> wrote: > > > >> So, assume I have 2 physical volumes, /dev/sda and /dev/sdb. > >> mkfs.btrfs -d raid1 /dev/sda /dev/sdb > >> What happens if I get a failure on /dev/sdb. > >> Assume no snapshots. > > > > "-d raid1" means mirrored data. Metadata is mirrored by default even > > on single drive volumes. > > > > If /dev/sdb faults then you should lose no data since every extent is > > replicated on both /dev/sda and /dev/sdb. If a bit error arises on > > either sda or sdb then a scrub will detect the error and it should > > automatically correct it using the replica on the other device. > > I'm sure these are silly questions I could google myself, but: what > happens with more than 2 devices? For example, if I used: > > mkfs.btrfs -d raid1 /dev/sda /dev/sdb /dev/sdc /dev/sdd > > It this going to be more like raid10?
No, that's still RAID1: two copies of every file, no striping. If you want striping+mirroring, turn on -d RAID10. > Also, can you add new devices "later" to an existing FS? E.g., let's > say we start with 2 devices (sda, sdb) -- can I later add more devices? Yes, and you can convert between RAID0, 1 and 10 in a live-but-slow fashion. -dsr- _______________________________________________ Discuss mailing list Discuss@blu.org http://lists.blu.org/mailman/listinfo/discuss
