In the last article, we looked at the big picture of what is involved in creating a SAN distance extension. In this article, we’re going to take a slightly closer look at the physical requirements and with luck we’ll be able to clear up some general confusion and misconceptions along the way.
There is a lot of information about these different elements available via a quick search on your favorite search engine. What I find, though, is that there is usually very little context that accompanies the descriptions or, at best, the authors assume that you may have more of an understanding about some of these technologies than you do. In this case, if I’m going to err it will likely be on the side of making it too accessible and in Plain English, which is something I can live with.
As usual, this is a mid-level view. There are many deep dives that will go into each subject in fine-toothed detail available on the web, but we’re going to stay focused on what you need to know for extending SANs across distances.
Again, this is a rather long post, but hopefully it will be useful as a reference point for you. Read More »
Tags: distance, FCIP, FCoE, Fibre Channel, iSCSI, Optics, Storage, xWDM
A long time ago I got asked to write about how to use Fibre Channel over Ethernet (FCoE) for distance. After all, we were getting the same question over and over:
What is the distance limitation for FCoE?
Now, the short answer for this can be checking out various data sheets for the Nexus 2000, Nexus 5500, Nexus 6000, Nexus 7000, or MDS 9X00 product lines. But it didn’t answer the most obvious follow-up questions: “Why?” and “How?”
Problem is, whenever you start talking about extending your storage connectivity over distance, there are many things to consider, including some things that many storage administrators (or architects) may not always remember to think about. The more I thought about this (and the longer it took to write down the answers), the more I realized that there needed to be a good explanation for how this worked.
Generally speaking, the propeller spins the ‘other way’ when it comes to storage distance.
To that end, I began writing down the things that affect the choice for selecting a distance solution, which involves more than just a storage protocol. And so the story grew. And grew. And then grew some more. And if you’ve ever read any blogs I’ve written on the Cisco site you’ll know I’m not known for my brevity to begin with! So, bookmark this article as a reference instead of general “light reading,” and with luck things will be clearer than when we started. Read More »
Tags: distance, FCIP, FCoE, Fibre Channel, iSCSI, MDS, nexus, Storage
What do you get when you cross iSCSI with lossless Ethernet? A lot of confusion.
I do quite a lot of presentations regarding converged networks, including Fibre Channel, whether native or over Ethernet (i.e., FCoE), iSCSI, NAS, etc. The hardest part about these presentations are combating some of the expectations that audiences have, considering they may come from server backgrounds, network backgrounds, or storage backgrounds.
Why is this important? Quite frankly, because like fish who don’t know they live in the water, they have come to grow unaware of their own environmental backgrounds. They tend to forget the assumptions with which they make their decisions. Ethernet and Fibre Channel networking people have very different fundamental philosophies about the way their networks run.
In the world of converged networks, this can cause some, er, unintended consequences. Read More »
Tags: DCB, ETS, FCoE, iSCSI, Lossless, PFC
Before I came to Cisco I still wrote about Fibre Channel over Ethernet (FCoE) and did my best to try to help edumificate people on how the technology works. One of the most popular things I’ve ever written, in fact, was a comparison between FCoE and another convergence technology, iSCSI. Since that time I’ve come to learn and understand a lot more about both technologies, how they relate to each other, and how storage networks are designed and implemented using them.
Since Demartek published the recent piece on multiprotocol connectivity, which included some comparisons on the protocols regarding latency I thought it might be a good time to revisit some of those questions. Read More »
Tags: FCoE, Fibre Channel, iSCSI
There are a lot of questions that people ask regarding Fibre Channel over Ethernet (FCoE), especially Multihop FCoE, and what happens when you put it into place inside the Data Center. For the most part, the questions have involved two particular threads: architecture and performance:
- What are my options with FCoE?
- Where can FCoE fit into my Data Center?
- Is there a performance penalty for running FCoE?
- How do Fibre Channel, FCoE, and iSCSI compare?
Demartek, a third-party research and analysis corporation, recently published an evaluation on Cisco’s Multiprotocol Connectivity and Multi-Topology solutions, which found that not only were the topology configurations extremely flexible for many different types of environments, but also found that even with multiple switches, multihop FCoE topologies can provide excellent performance within the Data Center.
Dennis Martin, founder and President of Demartek, will be presenting these findings and discussing his impressions of the technology in a live, public webinar, Thursday, August 9, at 1 p.m. ET/10 a.m. PT. We encourage you to attend to learn more about how these different technologies can fit inside the data center.
Tags: FCoE, Fibre Channel, iSCSI