I started a blog post about this topic over a week ago, and it grew into a huge article instead of a blog post. I'm hoping to have it ready for posting as an article yet this week, but there are some tidbits I thought I'd share outright. Less of a teaser than a "if you want just the overview, here's info with recommendations for further research topics".

In the world of storage virtualization there are a ton of options for enterprise IT to pursue, including SAN virtualization, NAS virtualization, Virtual Tape Libraries (VTLs), and iSCSI virtualization (new to you? Check out Dell/EqualLogic, who can present many arrays as one).

Each of these has its place, and each is a useful tool in the correct context The question is, what is the "correct context"? We'll delve into details in the article, but think of it this way, if you have a SAN, check out SAN virtualization. If you have a NAS, check out NAS virtualization - more generally known as unified directory services - if you do backup to disk, or are considering it, then VTLs are worth looking into, otherwise you don't need them. and iSCSI Virtualization is a good idea if you're a large iSCSI shop, so both of you get out there and check it out. Okay, just kidding, there are more than two, but it certainly doesn't have the adoption rates you would expect.

The point of all of these technologies is to optimize data storage and decrease access times. If you're constantly short of space on one array and never use another, then check them out. If your tape backup windows are astoundingly large, you can benefit from VTLs and one of the other technologies. And by benefit, I mean WOW! Your backup window could shrink by 90%. Currently, F5 only plays in the NAS virtualization space (though we have a solution to shrink backup windows too, it's not a VTL), so this is less advertisement and more recommendation that squeezing more out of your infrastructure - no matter the technology - is a good idea.

Of course each of these technologies has weaknesses also, and we'll get into those in the article. Only SAN virtualization is a killer - you lose the virtualization appliance and you lose the map of where everything is stored... But that's manageable with backups of the configuration and a good service agreement with the vendor.

Anyway, back to work on the article. For those in the US, hopefully you had a great time off - Joe enjoyed his time in Maui so much that he didn't come back. Some story about flights being canceled or something ;-).

Don.