Data storage solutions: How virtual can we get?

Updating data storage solutions can present many challenges. A storage expert tells why storage virtualisation may be your best bet in overcoming many of these.

Andrew Cross of Sol-TecAndrew Cross

 Ever since the summer holiday period ended, I have spent much of my time assisting midsized organisations (up to 1,000 users) explore the potential benefits of Hewlett-Packard Co.'s StorageWorks P4500 storage solutions. I've discovered a number of ways to enhance or replace shared storage resources within new or existing virtualised environments.

One key selling point of this storage solution is the Virtual SAN Appliance, or VSA software product that comes with it and which includes licenses free of charge with each P4500 product. This allows companies to reclaim unused or redundant physical storage and present the reclaimed storage space with the newly acquired physical P4500 SAN through the SAN-IQ management console. The feature is often overlooked during the evaluation process because most IT shops focus on other features the product offers. In fact, insiders at HP have expressed frustration that this value-add aspect is often thrown out with the packaging when the product arrives. The attention is always on the shiny new storage box with the twinkling lights.

So, do we really understand the value of a virtual storage area network? The current economic environment is forcing companies to squeeze maximum value from all purchases, whilst meeting demanding operational targets set by the CEO. The P4500's purchase scenario may mean finding a beneficial use for the SAN-IQ licenses shipped, such as utilising redundant storage hardware for disaster recovery (DR) or assisting a tiered data storage plan. However, for the CIO who wishes to virtualise servers and storage data in a regional/branch location or invest in more hardware for a more cost-efficient DR arrangement to facilitate this may be beyond justification. Therefore, the role of a virtualised SAN becomes clearer but still requires more investigation.

Storage virtualisation provides a layer between the host and the physical storage hardware. It presents single or multiple storage devices as a single resource ready for assignment. The storage devices can be redundant servers, network-attached storage or SANs. Based around the core of this idea is a set of features that depend on the storage virtualisation software being considered. Is this a new idea? No. Data storage virtualisation has been around for years and so have some of the products used to achieve it. LeftHand Networks, which HP acquired in 2008, was an early developer of SANs built around iSCSI and was founded in 1999. This is trusted technology.

However, HP is just one vendor with such an offering. A quick investigation will uncover several vendors that offer products with the same core ability. As with many virtualised software solutions, many have a no-cost version or are open source. In fact, the offerings available mirror the way server virtualisation products have been historically marketed. For example, VMware has a free version of its hypervisor server software along with paid-for licenses. Open-E Data Storage Software v6 offers a free version that allows up to 2 TB of storage to be presented and managed as a virtual SAN. This is offered with licences for larger data storage amounts. The only real limitation in the feature set is the storage it is able to present and therefore includes features like support for 10 Gigabit Ethernet, multiple NIC and data replication, and snapshots.

The current economic environment is forcing companies to squeeze maximum value from all purchases, whilst meeting demanding operational targets set by the CEO.


Andrew Cross, sales director, Sol-Tec Ltd,

 My curiosity, with free software stems, from the lack of discussion that such products generate when the subject of shared SAN storage solutions comes up. The concept of a virtualised SAN may not sit well with a CIO who is considering an investment in the company's primary data centre. The idea of having a physical platform is often more palatable, because you can physically see and justify the investment. However, server virtualisation on the x86 platform met the same inertia when VMware entered the market.

As with all infrastructure decisions, the choice of which topology to choose is based on personal experience, vendor marketing and perceived or actual risk, which often excludes established but lesser used technologies and, hence, excludes those benefits. Clearly, introducing newer technologies carries risk, but doesn't the same risk apply when introducing technologies from companies with products that stretch back to the previous century?

Technology advancements challenge traditional thinking within IT. The CEO wanting greater ROI from IT investments brings acute focus on squeezing out every last drop of value there is. So when working under this remit, ask yourself which areas of the storage infrastructure can such products bring value to. My recent discussions have highlighted two key areas of IT that, when discussed in conjunction with data storage virtualisation, have met the least resistance.

Better value from tiered storage solutions
A tiered storage solution strategy can bring benefits including extracting better value from storage costs. For some organisations, a storage refresh (so that their primary data can be moved to a faster performing platform) opens the opportunity to tier data storage and leaves static and less frequently used data to remain on slower disks.

If a change in storage vendor is also being considered, try taking a more inventive approach. For example, I recently advised on a customer's refresh project that a fresh purchase of P4500 storage for the company's primary data could be justified providing it could present their existing and lesser performing IBM storage as part of the same SAN for rarely used data. With HP's storage virtualisation offering, it could reclaim storage data from this redundant hardware, which meant it could extract more value from the previous investment.

Using thin provisioning technology will extract further value from the underlying storage hardware. Allowing a storage solution investment to be over-provisioned requires careful management, but the process is no different than managing bandwidth or any other metric. Professionally used, it can reduce ongoing expenditure and achieve additional return on investment.

For the virtualised data centre, these technologies can bring great benefits. If they present fresh challenges, they should still be welcomed. Virtualisation of data centre servers and switching are now widely adopted, so why not data storage virtualisation too?

Andrew Cross is the sales director at reseller Sol-Tec Ltd. and a contributor to

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