I missed the MVP summit last month in Redmond, but I heard there was some more discussion of the Server Message Block v2.2 (SMB2.2, also known previously as CIFS) coming in Windows Server (R) 8.
The big news is SMB2.2 now supports RDMA and can use InfiniBand (announced at SNIA Developer Conference last fall). It also supports RDMA over Ethernet via RoCE (see my Intel buys Qlogic’s Infiniband post) and iWARP.
SMB2.2 over InfiniBand performance
As reported last fall at the SNIA Developer Conference SMB2.2 using RDMA over InfiniBand reached over 3.7GB/sec with no server configuration changes using two QDR cards and 160K IOPs (the IOPs are from an SQLIO run using 8KB IOs, not SPECsfs2008). The pre-beta, SMB2.2 code was running on commodity server hardware using 32Gbps InfiniBand links. I couldn’t find any performance numbers with ROCE or iWARP but I would suspect running on 10GbE these would be much slower than InfiniBand.
Hints are that performance gets even better with the released versions of the code coming out in Windows Server 8.
SMB2.2 gets even faster than NFS
We have noted in the past that SMB (CIFS) on average, shows better throughput (IOPS) performance than NFS in SPECsfs2008 results (for example, see our latest Chart-of-the-Month post on SPECsfs results). However, those results were all at best SMB2 or even SMB1 results, and commonly using Ethernet links.
NFS already supports InfiniBand but I am unsure whether it makes use of RDMA. Nevertheless, the significant speed up shown here for SMB2.2 will potentially take SPECsfs2008 SMB2.2 performance up to a whole new level.
Why InfiniBand?
As you may recall, InfinBand is primarily deployed as a server to server interface and used extensively in the past for high performance computing environments. However nowadays, we find storage clusters, such as EMC Isilon, HP X9000 (Ibrix), IBM XIV and others using InfiniBand for their inter-node communications. The use of InfiniBand in these storage clusters is probably due primarily to its superior latency over Ethernet.
But InfiniBand has another advantage, fast data throughput, when using RDMA it can transfer data faster than almost any other networking protocol alive today. SMB2.2 takes advantage of this throughput boost by using RDMA only for large blocks of data and avoiding it for smaller blocks of data. Not sure what the cutoff is, but this would certainly help in large SQL database queries, disk copies, and any other large file data transfer operations.
Of course with 56Gbps FDR InfiniBand available today and faster transfer rates coming (see IBTA roadmap), there appears to be every reason to believe that superior throughput performance will continue at least for the foreseeable future. Better latency is also certain to be retained as well
Now that Intel’s pushing it, Mellanox continuing to push Infiniband and storage cluster’s using it more frequently, we may start to see more storage protocols supporting it.
We thought that FC only had Ethernet to worry about, with SMB2.2 moving to InfiniBand, NFS already supporting it, can a fully functional FCoIB be far behind?
