On Fri, 2 Nov 2012, Danny Al-Gaaf wrote: > Am 18.10.2012 04:18, schrieb Alex Elder: > > On 10/17/2012 09:15 PM, Christian Huang wrote: > >> Hi, > >> what is the maximum number of rbd devices that can be mapped on a > >> single host? > >> we recently did a test to mount a large number of rbd devices and > >> hit a wall around 230 > >> with the following message > > > > That sounds about right. We were just discussing this earlier > > this week. It's limited at the moment by the number of major > > device numbers available on the system, and I think you found > > that limit. We would obviously like to have a solution for > > this but we've only just started considering options. > > Any news on this? We have seen the same issues here. > > IMO the RBD code should to something similar to some other block drivers: > > 1) reserve a major block number for RBD in general (or use the number > returned from the register_blkdev call, if there is no number we can > reserve in general for RBD, see [1]) > > 2) Use this major number for all RBDs on this machine and handle each > new RBD via different minor numbers. > > If we can agree on this I would take a look into it and send a patch. We should probably do what SCSI does, where the minor for each device jumps by 16 to leave room for partitions. There was a thread on this a couple of weeks ago that mmy slow internet is preventing me from finding... :) sage -- 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
