Re:Torus: A distributed storage system by CoreOS
by ymse on Wednesday June 01, 2016 @09:01PM
(#11819605)
Native RDMA support for Ceph is still a ways off. The current implementation requires disabling Cephx authentication, which is a no-go in any environment where you can't completely trust every client (e.g. "cloud", where most current deployments/users live). It also hasn't seen much development since the initial proof-of-concept (still highly experimental).
That said, IPoIB should work just fine, and the main bottleneck currently is (Ethernet) latency. I'm running a couple of 1,6PB clusters (432 * 4TB) and can only get 20-60MBps on a single client with a 4kB block size, but got bored of benchmarking after saturating 5 concurrent 10Gb clients with a 4MB block size.
I do expect the RDMA situation to improve substantially over the next year or so, even if authentication will still be unsupported. The latter generally isn't a problem in HPC where stuff like GPFS lives (where you also have to trust every client). And they clearly want that market now that CephFS is finally deemed production ready.
That said, IPoIB should work just fine, and the main bottleneck currently is (Ethernet) latency. I'm running a couple of 1,6PB clusters (432 * 4TB) and can only get 20-60MBps on a single client with a 4kB block size, but got bored of benchmarking after saturating 5 concurrent 10Gb clients with a 4MB block size.
I do expect the RDMA situation to improve substantially over the next year or so, even if authentication will still be unsupported. The latter generally isn't a problem in HPC where stuff like GPFS lives (where you also have to trust every client). And they clearly want that market now that CephFS is finally deemed production ready.