On 04/05/2014 12:59 PM, Edward Ned Harvey (lopser) 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.
Agreed. FC also has the benefit of preventing over-subscription of a channel by design - you might saturate a link but you won't experience dropped frames. FC channel aggregation blows the socks off LACP as well; the usage on each individual channel is far more uniform than with LACP since an incoming are sent to the first channel with available credits rather than using some arbitrary hashing algorithm. Skylar _______________________________________________ Discuss mailing list [email protected] https://lists.lopsa.org/cgi-bin/mailman/listinfo/discuss This list provided by the League of Professional System Administrators http://lopsa.org/
