Virtual storage capacity management: an admin’s worst nightmare?

Most hear “server virtualization” and think: efficiency, ease of management, high availability and flexibility. But these benefits – the aim of sound IT planning – really only extend to the server (and in some cases application) layer. Administration, it turns out, is a whole other kettle of fish.

That’s because the complexities of introducing server virtualization into an environment force administrators to spend far more time than in the past on planning the overall capacity requirements of an environment and how to lay down data to ensure that the benefits virtualization brings to servers isn’t offset by problems to the storage environment.

Here are the three most common technology features created to help alleviate this pain point – as well as some of their pitfalls:

Thin Provisioning: Thin Provisioning allows administrators to show an OS/App/Hyper-visor an amount of storage they can grow into, while not actually allocating the physical space on the SAN/NAS. The SAN/NAS only allocates storage as data is written to it, so administrators can spend far less time planning — and only need to purchase and allocate what’s needed NOW, versus in 6 or 12 months.

DWhile thin provisioning provides a lot of value – extending existing capacity lifespan and lessening the number of tasks to manage virtual machines and data — it also causes issues. [Read more…]