Let me first discuss my pet project, SRDF/CE for MSCS. What is SRDF/CE you ask? Well it is EMC’s geographically dispersed clustering software. SRDF/CE is an EMC proprietary product that is used to integrate EMC’s SRDF technology with MSCS. Basically, it is the glue that combines HA from MSCS with the DR capabilities of SRDF remote mirroring to form a true geographic clustering solution. Upon failover, SRDF/CE issues the necessary SYMCLI commands to automatically RW enable the devices at the DR site then allowing the disks to come online at the DR location. This provides a fully automated DR solution with high availability.
It’s entirely possible that you work for a company that owns EMC hardware and you’re not aware of this little product. I’d love to hear from you if this is true. For some unknown reason, the marketing folks at EMC have never given this product any respect so it wouldn’t surprise me at all that you haven’t heard of this. One clear example would be to take a look at the EMC web site and attempt to find some information about this product. There used to be a good amount of info available for GeoSpan, but since the product “evolved” into SRDF/CE, the marketing has shifted away from the product. It really is upsetting to have spent so much time working on a project and then see that your company does not support the work that you’ve done. Am I bitter? I suppose so. I honestly don’t know how this product has survived and grown in popularity over the years.
SRDF/CE was originally called GeoSpan for MSCS. Many moons ago, the company decided to change the name to align with other product naming conventions and this became SRDF/Cluster Enabler…rolls off the tongue, doesn’t it? Anyway, some good and some bad came with this name change. The good was that we added some wizards to help with the install. The GeoSpan install was a nightmare and practically could never be installed properly without the assistance of someone that had previously installed the product. Also, we got rid of some of the ugliness of GeoSpan which really wasn’t a GUI. We made the SRDF/CE GUI a MMC snap-in so it was now certainly a GUI product. The bad…well, we added some additional checking which caused big performance issues on the RDF links. This is one issue that still plagues us today and has left a bad impression at a few customer sites. Other bad news, we added some instability to a product that is supposed to be used in a HA environment. Early versions of SRDF/CE were infamous for causing database corruption which triggered unnecessary failures in a cluster environment.
Over the past couple of years, SRDF/CE has significantly improved its stability and performance. We still need to tweak the registry and some other software settings to get the RDF link performance just right, but we’re definitely releasing a better product these days.
A few years ago, someone (I think it was a customer) asked me if I would use SRDF/CE in my environment if I were an EMC customer. I had to think really hard about this one since I work in a support center and really only see the bad side of our products…believe it or not, customers never call in to tell us how well things are running. J My answer at that time was something like since I knew the ins and outs of the product, I would’ve been comfortable implementing this in my own environment. I don’t know if that’s very comforting endorsement, but it was the truth.
Today, I really do enjoy the SRDF/CE product and would easily recommend implementing this into any customer’s site…including my own were I an EMC customer. The newer versions (versions 2.1 or higher) have really made significant improvements over the first couple of releases and continue to evolve for the better.