I get 950 Mbps with iperf (w/o jumbo frames). Actual disk to disk, or even disk to memory transfer speeds are at 30MB/s. If you'd read the article I linked to you'd know that.

Actual protocols are a LOT slower than just slamming as many bits as possible through a pipe.

The days of network being faster than disk are over.

Gig-E speed is about 30MB/s in the real world. This is with a crossover cable, machine to machine. I've tested and verified this over a number of platforms, including expensive server systems.

Cheap terabyte single disks these days can do 80MB/s.

The only reason to go with raid is for redundancy, or better handling of simultaneous connections.

Read this for a more in depth analysis: http://www.codinghorror.com/blog/archives/000339.html

That USED to be true. It's not the hard drive, all the layers that get put in between when you access a disk over the network. Modern hard drives can easily do 60MB/s sustained.

For instance, I have a couple raid6 arrays which clock in at about 250 MB/s and 150MB/s natively. If I hook that machine up directly to another machine's ethernet port I only get about 30MB/s sharing the device w/ iSCSI. SMB and NFS yield similar results. This is true even though I can get over 900Mbps using iperf.

Sharing disks over gig-e sucks when you actually need throughput. It's great for when you just need to expand a SAN and speed is secondary. I've heard that bonding two Gig-e cards doesn't realize much of an improvement FWIW, so I assume latency is part of the reason it's slower.