Thank you for the test. I will do some tests also (later as now I do not have a space for it) - when you disconnected one disc (or deleted a file) did you try btrfs fi balance? I wonder if missing files simply "disappears" or not, because in the fact they are present as metadata information only. if not, then would be necessary to write a small script which will check all the files and report missing/broken ones (or use aufs on top).
When I use "-d single" option, then preffered way is fill the disc completelly and then continue with another disc. And you are right, there is no guarantee that some files wil not be spread over all three (or more) disc. (as I understand it from docs). On Mon, Mar 18, 2013 at 9:03 PM, Jan Beranek <jan233...@gmail.com> wrote: > Thank you for your test. > > I will do some tests also (later as now I do not have a space for it) - when > you disconnected one disc (or deleted a file) did you try btrfs fi balance? > I wonder if missing files simply "disappears" or not, because in the fact > they are present as metadata information only. if not, then would be > necessary to write a small script which will check all the files and report > missing/broken ones (or use aufs on top). > > When I use "-d single" option, then preffered way is fill the disc > completelly and then continue with another disc. And you are right, there is > no guarantee that some files wil not be spread over all three (or more) > disc. (as I understand it from docs). > > > On Mon, Mar 18, 2013 at 8:24 PM, cwillu <cwi...@cwillu.com> wrote: >> >> On Mon, Mar 18, 2013 at 12:32 PM, Jan Beranek <jan233...@gmail.com> wrote: >> > Hi all, >> > I'm preparing a strorage pool for large data with quite low importance >> > - there will be at least 3 hdd in "-d single" and "-m raid1" >> > configuration. >> > >> > mkfs.btrfs -d single -m raid1 /dev/sda /dev/sdb /dec/sdc >> > >> > What happen if one hdd fails? Do I lost everything from all three >> > discs or only data from one disc? (if from only one disc, then is it >> > acceptable otherwise not...) >> >> I just finished doing some testing to check: It will work, kinda sorta. >> >> You'll be forced to mount read-only, and any reads of file extents >> that existed on the missing disk will return an io error. As I >> understand it, single doesn't force files to be on a single disk, >> instead it _doesn't_ force them to be _several_ disks; the implication >> being that a large file (say, a 4gb movie) may still end up with >> pieces on each disk. > > > > > -- > S pozdravem > > Jan Beránek -- S pozdravem Jan Beránek -- 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
