Interesting question. To support FC, FCoE and FICON over a WAN we would need a network capable of layer 2 operation. Dark fiber typically. Expensive! IP has obvious benefits in that (even good ones with SLAs and not overbooked) they are relatively cheap and easily available.

Very enlightening for me. I am not an IT expert but even so your descriptions were understandable and cleared up some fuzzy areas for me. I am a last mile transport provider via my own fiber network. I am especially interested in your comments on FCIP and ISCSI –

“Note: FCIP and iSCSI don’t have any mechanism to deal with LAN overloading and as a result they are prone to delays and frame loss. As a result they not suitable in larger environments where engineered levels of performance and resilience are required. Their main benefit is that they can be implemented at low cost on an existing LAN.”

Here is my question: If I am providing WAN transport at the Layer2 Ethernet level which is not oversubscribed and carries latency and packet loss SLA, would FCIP and ISCSI be a viable option for a larger environment as you mentioned above? If so what kind of cost savings on the hardware/software might a company epxect versus going with FC, FICON or FCOE?

I know it is a broad question but if you can give some back of the napkin or rule of thumb metrics it would be very helpful.

Thanks
Terry

You got it completely right. One of the biggest problems is that the SAN is a black hole that we hope to route our valuable traffic through. We can’t see what is going on inside, all we can do is hope that it will work. Because we are so risk averse and can’t afford to be overloaded or have an outage, we over-provision.

SANs actually work quite well except when they don’t and then we have a nightmare.

Thanks

Steve

This is a great start on a very fundamental question: What is “Good” SAN Design? I want to put some of your points in context.

If we designed office space the way we design SANs, the standard office would be 5,000 square feet!

The fact is that there is massive, habit-based over-provisioning that is not only extremely costly but actually adds risk… because there are more things that can go wrong.

The interesting thing about storage infrastructure is that you don’t have to virtualize to consolidate. You just need to measure…twice, cut once.

http://www.virtualinstruments.com/uhrdahlblog/