On Tue, Apr 5, 2016 at 10:30 AM, Sebastien Han <shan@xxxxxxxxxx> wrote: > Wido, I just discussed that with Sam last week and it seems that > bcache allocates a minor of 1 when creating the device. > Sam ended up writing this: > https://yaple.net/2016/03/31/bcache-partitions-and-dkms/ > The fix is not complex not sure why it is not part of bcache yet... I think it's just that no one complained loud enough. > > Not sure if it's ceph-disk's job to do all of this with bcache though... > We might need to check with the bache guys what are their plans about this. > If this will go through at some point we might just wait, if not we > could implement the partition trick on ceph-disk. Making something like this go through shouldn't be a problem. Sam's patch is a bit of quick hack though - it messes up bcache device IDs and also limits the number of partitions to 16. Better to avoid another hard-coded constant, if possible. # ls -lh /dev/bcache* brw-rw---- 1 root disk 254, 0 Mar 31 20:17 /dev/bcache0 brw-rw---- 1 root disk 254, 1 Mar 31 20:17 /dev/bcache0p1 brw-rw---- 1 root disk 254, 16 Mar 31 20:17 /dev/bcache16 brw-rw---- 1 root disk 254, 17 Mar 31 20:17 /dev/bcache16p1 brw-rw---- 1 root disk 254, 32 Mar 31 20:17 /dev/bcache32 brw-rw---- 1 root disk 254, 33 Mar 31 20:17 /dev/bcache32p1 We had to solve almost exactly this problem in rbd. I can submit a patch for bcache if it helps ceph-disk in the long run. Thanks, Ilya -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
