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Not Your Father’s Protocol Analyzer
When we talk to prospective new customers and we’re explaining who we are and where we came from, we mention our Finisar Protocol Analyzer legacy. It doesn’t always work in our favor, as I found recently when one U.S. financial institution said “Yeah, we bought one of those a few years ago. It was expensive, no one knows how to use it and it sits in the corner.” I was glad that our account team heard this first-hand, so they could explain that this technology has come a long way. For those of you who might know us from the Protocol Analyzer days, we’ve tremendously expanded on that legacy, and here’s a quick summary of what’s changed.
Protocol Analyzers were traditionally used to reactively troubleshoot FC SAN problems. They capture traffic and report performance metrics and data errors in real time, whenever there is live traffic over any individually monitored Fibre Channel link. Users can view MB/s, Kframes/sec, utilization, frame errors, and physical layer errors from each direction of the link. Protocol Analyzers are typically dedicated to only one link at a time and not a view of the entire SAN, and they are of most use if you can read and understand fibre channel traces. If you can’t, there are some week-long workshops available you can attend to learn. Or, you can simply join the 21st century and check out the next generation fibre channel monitoring solution, VirtualWisdom and our hardware probes.
Like Fibre Channel Protocol Analzers, VirtualWisdom connects physically to the fibre channel itself, so it sees every frame. To the core value of these analyzers, VirtualWisdom adds an interface that’s designed to be used by the typical IT administrator. Philosophically, the biggest change is that VirtualWisdom in effect acts as a proactive SAN admin; it finds and alerts you to problems before they affect users. And every IT admin I talk to says the same thing … the hard part is finding the problem, not fixing the problem. Specifically, VirtualWisdom adds …
- Continuous real-time monitoring and filtering that calculates statistics based on seeing all the fibre channel frames that are traveling through the entire fibre channel SAN - up to many 1000s of links, not just one, as a Protocol Analyzer does.
- Immediate proof whether or not the SAN is the cause of application slowdowns.
- “What if” modeling to predict the effect on application performance of adding or re-deploying virtual machines or changing SAN I/O infrastructure configurations.
- Comprehensive event recording and real-time capture capabilities for finding intermittent problems and supporting SLAs.
- Performance trending of SAN device components to identify hardware degradation to enable IT managers to preemptively replace components before they actually fail.
- In-depth fibre channel network statistics such as pending exchanges to tune queue depths for maximum application performance.
- Ability to determine if configuration changes are affecting application performance by examining SAN latency.
So, to summarize, Protocol Analyzers are designed to be used to troubleshoot existing problems on a known bad link. VirtualWisdom is often considered to be a “virtual SAN administrator” that proactively monitors all of the links on a SAN and alerts to potential problems before they cause application slowdowns or outages.

I would further add that this “Yeah, we bought one of those Xgigs a few years ago. It was expensive, no one knows how to use it and it sits in the corner.” sentiment is also pushed by a major switch vendor. I happened to be at their RTP facility doing a deep dive w/their product engineers a few months back and when I asked why they weren’t at least having the TAPs incorporated into the Fibre Channel portions of both of their recent “Virtualization offerings w/VMware and EMC and VMware and NetApp they told me that their SPAN functionality negated the need for it. However, well, if you have a switch that is “over subscribed” at 4Gbps FC (let alone at 8Gbps FC) you’ll find that typically when the switch is being over subscribed is one of the times that you’d want to look at traffic. In this particular vendor’s case you’d then quickly realize that when the switch is stressing b/c of said over subscription it “intelligently” disables what it considers “unnecessary” services, one of which is SPAN….