Storage Virtualization to Reduce Cost of Copies
by David Merrill on May 16, 2012
I am in the middle of a multi-part blog series on some of the secondary cost benefits of storage virtualization. I posted an entry last week on virtualization’s impact on maintenance, and now will talk about the cost of copies.
Copies are an interesting topic. Copied data can be different from data that can be de-duplicated, or data that is thinned. I have read analyst research that suggests a structured DB can often have 7-12 copies of that database within the enterprise. Copies can be strategic for testing, development, protection, data mining, etc. The costs of copies tend to range from 2-5% of (total, blended) storage TCO, and upwards of 20% of the depreciation expense portion of TCO. Most times, as a consultant, we are not in a position to argue or challenge the number of copies that a customer may create, but rather tend to help customers reduce the cost of these copies. At the core of the cost issue is that copies tend to be made and kept within the same tier as the master file or database.
Virtualization, either at the LUN or array level, can have an impact on the cost of these copies. The key is to not necessarily be focused on reducing the number of copies, but the cost of copies. Copies can be relegated to lower tiers of storage, storage that has a lower cost of ownership and price. Lower cost tiers, that may be appropriate for copied data, may not have the full/frequent backup protection, probably will not have disaster protection, lower management overhead and a lower cost of the older tier of storage. This is where virtualization can help; by virtualizing older tiers that still have some useful life in them, these arrays can be a good cost-target for copies.
I had a customer a few years ago, that was running on HDS 3rd generation virtualization arrays (we are now on our 5th). As part of sweating the assets, when an array came off of lease, they would purchase a T&M maintenance contract, and demote the array to tier 3 or tier 4 (depending on the drive type, cache, ports, etc.). They would try to keep these older arrays 18-24 months beyond the depreciation or warranty period, and saw this as a perfect location for most (but not all) of the copy capacity needed for development and production. They employed this enterprise-class technology with heterogeneous arrays from IBM, EMC and SUN. The virtualization architecture allowed these subordinate arrays to inherit some of the qualities and capabilities from the host virtualization platform, but the approach was a minimalist style to hold down costs. These arrays turned into tier 3 and 4 landing zones, and took considerable capacity off of the higher tiered arrays. Dynamic tiering or auto-tiering can also be bundled with virtualization for a compounded benefit, but on its own the virtualized assets provided a lower cost tier, and therefore a lower cost of copies.
