On Mon, Jul 27, 2015 at 11:38 PM, Wyllys Ingersoll <wyllys.ingersoll@xxxxxxxxxxxxxx> wrote: > I found a thread from 2012 talking about the maximum number of RBD > devices that can be mapped, it seems to cap out at around 228. There > was discussion about possibly fixing this by using a registered/fixed > major block device and bumping the minor device number for each new > mapping. > > http://www.spinics.net/lists/ceph-devel/msg09362.html > > Did this ever progress any further or was an official bug ever filed? > Im seeing this issue now and was just wondering if there are > workarounds (other than not creating that many mappings). What are your kernel and ceph versions? It's been fixed in 3.14 with the addition of single_major parameter to rbd.ko. It's off by default because old userspace doesn't know how to deal with it. If you are on 3.14 or later and your userspace is new enough (0.75 or later IIRC), rbd map will load with single_major=Y. The new theoretical limit is 65536 rbd devices, but I must confess I haven't tried to map more than ~4000. 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
