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1Gb/s Fibre Channel throughput vs Gigabit Ethernet throughput

Given 1 Gb/s Fibre Channel HBA vs an Gigabit Ethernet connection,
What would be faster in terms of throughput?
Any url links would be appreciated.  
FYI we are using Emulex LP8000 HBA cards  
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rawalker58
Asked:
rawalker58
1 Solution
 
Lee W, MVPTechnology and Business Process AdvisorCommented:
I would say the Fibre channel.  Because most network protocols have significant overhead that would lower the achieved data throughput.  Especially if your gig ethernet connection was copper and not fibre based.
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rawalker58Author Commented:
Thank you for your reply. I believe this is correct as well. However I need data to back this up.
Do you know of any links or data to substantiate this?
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411monkCommented:
If your talking FC versus iSCSI, absoloutely FC is faster on a 1GB pipe.  1GB fiber and 1GB copper is the same througput, copper being limited by distance.  The protocol you run on the physical cabling will be the determining factor.  iSCSI inputs variables such as TOE cards and offloading processing that places it second to FC.
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Steve McCarthy, MCSE, MCSA, MCP x8, Network+, i-Net+, A+, CIWA, CCNA, FDLE FCIC, HIPAA Security OfficerIT Consultant, Network Engineer, Windows Network Administrator, VMware AdministratorCommented:
I would tend to agree with 411monk.  1gb Fiber and 1gb copper are the same in throughput, however the distance limitations are different.  When you are talking TCP/IP for example, once it gets down to the physical layer, it's the same anyway for fiber or copper.  So.......  Do you need the distance or to save some money.  If you want a cheap upgrade, Dell 24 port Gigabit switches run less than $400, so you can get a big bang for the buck with gigabit speed.

Steve
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Duncan MeyersCommented:
FC real throughput is 100 MegaByte/sec (once you've taken out overheads etc) for the LP8000 (1Gb fibre attach). Gigabit ethernet is around 60-80 Megabytes per second. What is interesting though, is that an LP8000 on PCI bus connected to older storage will achieve 87MB/s write bandwidth and 85 MB/s read bandwidth. A QLogic QLA2340 (2Gb or 200MB/s card) achieves 130MB/s write and 190 MB/s read in a PCI bus. Put the same card in a PCI-X bus and that leaps to 194MB/s write and 190 MB/s read. You get similar figures for the Emulex LP9802.

What it all boils down to is that the limiting factor is the server itself.  It takes an enormous amount of CPU grunt to saturate the FC connection. In real world usage, you simply won't hit the bandwidth limitations of the FC interconnect. You'll hit CPU utilization, memory bandwidth or PCI bus limits first.

Having said all that I would always use FC in a SAN - even though it is more expensive than iSCSI or iFCP. You get a dedicated network for your storage that is designed for this application. And, as 411monk rightly points out, FC adapters do the protocol processing for you rather than offloading it to the CPU as in IP (some network cards excepted of course)
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Steve McCarthy, MCSE, MCSA, MCP x8, Network+, i-Net+, A+, CIWA, CCNA, FDLE FCIC, HIPAA Security OfficerIT Consultant, Network Engineer, Windows Network Administrator, VMware AdministratorCommented:
I would ask for a share.  As all were good answers, I would recommend a split among the 4.
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Duncan MeyersCommented:
No opinion...
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