Thanks, Edward. I fully agree with you: a 40Gb infiniband network is going to have significantly better performance and lower latency than a 10Gb Ethernet network.
As far as sustainable throughput, even assuming a 1Gbps per drive throughput, I'm not sure how that's relevant to the line protocols that we're discussing. If you're saying that at 1Gbps/drive, a single 10Gb link can support 10 drives, I'll agree again, and also that an 8Gb link will support 8 drives and a 40Gb link will support 40 drives. But drive performance isn't all about sustained throughput, and if we're talking about Oracle databases, it really has almost nothing to do with sustained throughput and a lot to do with iops, because it's more random access than sequential, though again that depends a lot on the database and the application using it. -Adam On Sat, Apr 5, 2014 at 3:59 PM, Edward Ned Harvey (lopser) < [email protected]> wrote: > > From: [email protected] [mailto:discuss- > > [email protected]] On Behalf Of Adam Levin > > > > 2) It used to be the case that 1Gb Ethernet, even using LACP or other > > aggregation protocols, couldn't keep up with FC. FC is a more efficient > > protocol than NFS. However, now that we have 10Gb Ethernet, it's really > no > > longer an issue. > > I disagree bigtime. Even if you run iscsi over 10Ge, it still has to go > through all the mac/ip/application layers, not to mention, the 10Ge switch, > probably buffering, store and forward, etc. If you have a network such as > Infiniband or Fibre Channel, you're able to skip all those and use DMA > directly, which greatly decreases latency. Also, the speed of even the > slowest IB network is around 40 Gbit, while ether maxes out at 10Gbit. > > Whether using SSD or HDD, the sustainable throughput of each individual > device is around 1Gbit. So the max performance of a 10Ge network is on-par > with 10 disks. Which would be a pathetically small SAN. >
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