"Stranded storage" is the term applied to storage devices that are in some way separated from the main body of storage, and because of that can neither be well managed nor used efficiently. Most often, storage is stranded because it is connected directly to the server that uses it.
Direct-attached storage (DAS) is still the most common form of storage with small and midsize businesses (SMB), and in fact represents a large segment of enterprise storage as well.
Occasionally, storage on distributed storage systems also gets stranded because it cannot be administered from a centralized management system. This most often occurs with remote storage-area networks (SAN), but "remote" just as often turns out to be less a question of distance and more one of simply being disconnected.
Neither of these are good reasons for having a lot of storage stranded about your IT shop, but at least they are understandable excuses.
Less acceptable reasons for having unused storage include not inventorying all the devices your IT group won following your company's latest acquisition of a competitor, and all those assets from closed-down projects that have never been reallocated to productive operations. Probably every site has wasted assets such as these.
What is perhaps most embarrassing about this may be the fact that in many cases the only person in the company who has anything approaching an accurate inventory of such devices is the guy in the Accounts Payable Department who pays out on the monthly maintenance contracts.
A lot of solutions are now available that are useful for discovering stranded or under-used DAS and networked storage.
The best part about many of them is that they provide payback almost immediately when they identify all those assets you never knew you had. The payback in this case comes in the form of delaying the capital outlay for all that new storage you thought you were going to have to buy just to keep pace with your existing needs.
Wonder what this might mean for you? Assume first that you are one of those sites that grows its storage by 25% each year. Next, assume that at your site - like many Microsoft enterprise environments - more than 50% of the storage is unused. Reclaiming half of your storage will delay capital expenditure for storage hardware by at least one year. The disk vendors might not like you much for doing this, but think of the extra cash on hand for the holiday parties.
Solutions for the stranded storage problem appear in all sorts of technology from a wide variety of vendors. More on this next time.
Mike Karp is senior analyst with Enterprise Management Associates, focusing on storage, storage management and the methodology that brings these issues into the marketplace. He has spent more than 20 years in storage, systems management and telecommunications.