• SAN Best Practices
February 7th, 2011

Not Your Father’s Protocol Analyzer

Jim Bahn

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.