Thin provisioning has become a common feature offered by the storage industry, and today there are many different hardware and software products available from suppliers. All the various vendors seem to have differing opinions on what should be achieved and how to go about achieving it. Whether or not these objectives are actually accomplished seems almost inconsequential.
As most users have discovered, not all offerings are created equal - often because of the lack of technology standards in IT - so there are a few things to look out for.
It is common for IT vendors to continually reinvent themselves by coming up with new innovations and convincing customers to purchase them, even though there may not be a specific requirement for them. Financial constraints are pushing people to evaluate the need for the new technologies, and whether the benefits are real or necessary.
With thin provisioning the benefits are simple: a reduction in the amount of storage purchased and an improvement in the utilisation of storage assets.
Most audits and industry analyst reports indicate data centres are using 25%-30% of their capacity in a typical open systems environment. This means that 70c in every rand is wasted. I suspect this is a statistic most financial managers are unaware of and, if they are, I can imagine the justification for the next capital expenditure may prove extremely difficult.
Achieve improved utilisation
Financial constraints are pushing people to evaluate the need for the new test technologies, and whether the benefits are real or necessary.
Adam Day is product manager at SYSDBA.
Thin provisioning, when used correctly, can be an extremely effective tool in improving ROI on storage, by pushing utilisation levels above 50%, effectively halving storage costs. However, one needs to ensure the functionality does not introduce complexity or restrictions.
With thin provisioning there are some important 'gotchas' to watch out for:
* Simplicity? The functionality must be transparent and easy to deploy - if companies need to employ professional services or hire gurus to manage it, they have lost the TCO or ROI benefits gained from deploying it in the first place.
* Is it supported in production? It is not much use if companies can't get the benefits across the breadth of their data store. Most development or test environments are a small portion of the IT pool, and companies want to realise as much benefit as possible from the reduction in their storage needs.
* Does it affect performance? Storage needs to maintain a high level of performance so as to not affect SLAs or user experience.
* Can users overprovision storage? Many of the products allow users to provision up to what they have purchased. One of the major reasons for thin provisioning is the ability to overprovision resources - this is an accepted practice in server virtualisation, so why should storage be different?
* How granular is it? There needs to be fine-grained deployment of resources - when data is written it should use as little disk capacity as possible. Be sure to check what portion of the pool is consumed when a write occurs.
* Does it require a dedicated pool? The entire storage repository should be available for thin provisioning. If companies have to carve up resources or set aside dedicated areas for this functionality they have removed the benefits of the technology.
When considering the implementation of thin provisioning, bear in mind that not all offerings are equal, and a few merely pay lip service to what is becoming a must-have feature of storage.
Be sure to get detailed information about how the company's specific implementation works. Also, check out what the roadmap for the technology is: there are interesting new developments being touted, for example re-thinning of “thin environments”, so investigate whether the company will reap these benefits in the future.
Staying thin
New innovations need to progress and expand, and this is also the case with thin provisioning. For example, those who have the occasional beer or enjoy food are aware that sometimes it is not getting thin, but staying thin, that can be difficult. The same rings true for thin storage.
Once a thin environment is deployed it can quickly become “fat”. Modifying the file system by deleting files or redeploying virtual machines consumes space, leaving the data marked as consumed and no longer thin. That ability to reclaim “lost” space on a thinly provisioned storage volume is essential.
It is increasingly important with today's budgets to squeeze every rand out of assets; thin provisioning is an important technology for storage networks as long as companies make sure they implement a viable solution and deploy it correctly.
For advice on thin provisioning or how to best use it, contact me on adam.day@sysdba.com and I will supply industry analyst reports or advice on the technology.
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