Hi Ilya, On 05/04/2016 11:26, Ilya Dryomov wrote: > 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. It would help. Implementing a workaround in ceph-disk to compensate for the fact that bcache does not support partitioning feels much better when there is hope it will eventually be removed :-) Cheers > > 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 > -- Loïc Dachary, Artisan Logiciel Libre -- 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
