Written by W. Curtis Preston
Thursday, 09 August 2007 15:06
They need to stop calling it that. No one installing 10 GbE is getting 10 GbE performance, so why should they be allowed to call it that?
(Someone replied to my query, and there is now a new blog entry about what they said.)
The first lie was GbE. For years we couldn't get anything more than 50-60 MB/s. Now you can get GbE performance by using jumbo frames and/or a TCP Offload Engine (TOE) card, but hey, at least you can get it.
Now let's talk about 10 GbE. Go ahead: pay way too much for a 10 GbE NIC. Then install it and tell me what your throughput is. The best I've ever heard of is just over 200 MB/s. Lessee... 200 * 8 = 1600. 10 Gb = 10,000 Mb/s. 10,000... 1600...
That would be a 625% exaggeration. I think it's safe to call that a LIE.
The Intel NIC I pointed out isn't a TOE, you say? Alright, buy the Chelsio 10 GbE TOE NIC. They were BRAGGING that it can go as fast as 200 MB/s ! Oh, by the way, it's also really hard to get TOEs for anything but Windows.
So why do people think that GbE (and 10 GbE, 40 GbE, etc) is going to replace Fibre Channel? At least with 2 Gb or 4 Gb FC, I actually get 2 or4 Gb.
I think the core problem is the IP protocol. It's designed to send data across the world, not across a datacenter. There's so much overhead in it that's needed when you're sending data across the world. But that overhead isn't needed (and yet is still used) when sending data across a datacenter.
Fibre Channel, on the other hand, assumes the transport is local and that the frames are sent and received in order. That makes it great for datacenter transmission, but bad for long distance transmission. It's frame size is much larger than IP's, and it doesn't have to do all that work of putting frames back into order because they are sent and received in order.
Tell me I'm wrong!
Tell me you've put in a 10 GbE NIC and tested it and got anywhere near 10 Gb/s. That would translate into 1200 MB/s, by the way.
Please tell me I'm wrong. I really want to be. (But I don't think I am.)
Update: None of the people in this discussion on the NetBackup mailing list seem to think I'm wrong. Also, I have attempted to contact the person at Neterion who left a comment, but I haven't heard back. (I asked to talk to one of these customers that's getting 10 GbE speed with 10 GbE.)