At a time when you cannot open a tech magazine without being bombarded with articles on the cloud, it is curious that such little attention has been paid to the role of virtualised storage.
An integral part of any cloud offering, virtual storage allows for almost unlimited flexibility when it comes to how data is treated. Understandably, it was the cost savings associated with this kind of system that first attracted attention from companies, but according to industry experts the reasons why customers are continuing to virtualise their storage are now much more varied.
"In the past it was all about cost-people choose to explore virtualised storage and cloud style solutions for their businesses because they knew they could make savings by doing so. If they were smart, they could save as much as 20% a year on their operating expenditure," said Jason Ward, country manager for EMC.
"But now those savings have been made, and whatever costs that could have been cut have been cut. Now the primary motivator is time to market-business agility and the ability to embrace new applications faster is something we see customers not just asking for, but demanding."
Out the door
What Ward means by time to market is how quickly it is possible to go from taking a strategic decision to offer a new service or product, to getting it up and out the door. Where traditionally this would have required time and money, the same thing can now be done using virtualised infrastructure in a fraction of the time.
"We have customers who are virtualising their whole SAP environment, so when they want to roll out a new business warehouse project, or implement AP or sales order processing, the time it takes them to do it has been cut from months back to days. They can spin up a new virtual instance of their SAP environment, do tests and development and do user acceptance testing much faster, and then roll it out quickly," he said.
The central characteristic of virtualisation is the decoupling of the software and hardware so that the software is able to act as an independent, portable, dynamic agent without being reliant on the hardware underneath.
"The whole idea is that hardware becomes independent of the software, so that virtual machines, in the case of servers, and virtual storage can be moved and transposed between hardware," said Rupert Collier, regional manager for DataCore. "In the case of hardware it doesn’t matter what it is, and in the case of cloud it doesn’t matter where it is."
Four way
According to Collier, there are four main reasons why it is worth virtualising storage-cost, availability, management and performance.
"A lot of the customers we speak to talk about vendor lock-in-if you buy vendor X then you have to continue buying vendor X because it won’t talk to vendor Y. They may have got a significant discount at the beginning, especially if they’re a large customer, but woe betide them trying to do anything after that because they are locked in at that point," he said.
"So we see a lot of desire from customers to extricate themselves from vendor lock-in, not just in terms of choice of disk type or technology but choice of vendor. They don’t want to be tied down to one specific vendor because they want to be in a position to add whatever disk they like, whenever they like, as good deals appear in the market."
Collier said the second factor, availability, is also a major draw.
"When it comes to business continuity and disaster recovery, a storage hypervisor really gives flexibility to do things in the way that best suits the organisation, and that’s crucial to a lot of customers," he said.
Datacore offers data protection services at three levels-a synchronous mirror between two nodes, normally in close locations with continuous data protection; a log-based system which allows you to roll back and start from a saved point in the event of a failure, and an asynchronous replication link out to the cloud or a dedicated back-up site.
"The big issue is that virtualised storage can be used to eliminate the single point of failure, but just what that is depends on the customer and the kind of data it has. Some consider a single disk to be a single point of failure, some a rack, while others would go up to an entire data centre or even a whole country," Collier said.
The third compelling reason to virtualise storage, in Collier’s opinion, is the management and productivity gain that can follow.
Management
"A lot of storage vendors have their own graphical user interfaces (GUI) and management systems for their software and hardware stacks, and it can take a lot of time and energy for the customer to learn the various tips and tricks to dealing with them," he said.
"To have one overarching storage hypervisor that sits on top of all hardware, regardless of who it’s made by, is a massive plus. It enables management to happen much more rationally and planning to be done more accurately."
The fourth in the set is data performance-in other words how quickly the right data can be made available to the right application.
"When customers require immediate storage response, when their storage isn’t just a data repository but is actually an integral part of an application getting up and running, then performance is an issue. When you’re talking about rapid response type applications like security systems or desktop virtualisation, then you need that," said Collier.
"With widespread desktop virtualisation, you also start to encounter issues like bootstorming, when everyone tries to log into their virtual desktops at the same time, and you need fast disks for that."
Lock-in
According to Nigel Tozer, business development director with Commvault, companies thinking of virtualising in order to liberate themselves from vendor lock-in should think carefully before doing so.
"One thing I see on an almost daily basis is companies looking to implement virtual systems themselves who rip all the servers out of their racks, and then quick fill them with disk because they’re looking forward to getting all this space, power and cooling back. But a lot of the time they can end up just as burnt on the storage side as they were with the server side," he said.
"One of the big problems, particularly in the larger virtualised environments, is that it’s difficult to predict which disks are going to get hot, and you can’t always spread things around as effectively as you’d like-virtual storage systems can really help with that. The other thing that’s attractive is that there is a lot of legacy disk out there that’s perfectly good in terms of space and performance, but you really need networked storage to get the most out of those systems. Virtualising that back into the fold can give that a new lease of life and some nice cost savings."
Server focus
While decoupling hardware and software through virtualisation has become an accepted practice, and a crucial part of the ubiquitous cloud computing offerings out there, much of the attention surrounding the technicalities of how these technologies work has focused on the server component.
At the same time, the virtualised storage component so crucial to any true cloud service hasn’t been so well examined in media reports. While the core ideas are simple enough-any desktop PC or even smartphone connected to the net with a Dropbox or Skydrive account is effectively using virtualised storage-the enterprise class versions of the same technology are in a different league.
"Virtualised storage is a core part of the cloud offering, a core part of the idea that cloud can offer a high speed of implementation. If you have a self-service portal in the cloud or some kind of server utility offering, then having a traditional storage platform at the back end places a limit on what you can do with this very flexible cloud utility at the front end," said Greg Moore, storage specialist with Dell.
"Virtualised storage removes all the limitations of traditional storage arrays, effectively bringing it into an area where physical hardware-disks, controllers, fibre channel ports, iSCSI ports, connectivity to the storage area network (SAN)-is all virtualised."
Fluid data
Dell acquired Compellent Technologies towards the end of 2010, and now offers virtualised storage technologies under the brand Dell Compellent that allows stored data in an extremely fluid way.
"Using this technology, you could create a volume and write to it at RAID 10, read from it at RAID 5 and RAID 6, all at the same time. You can have the speed of RAID 10 and the capacity advantage of RAID 5. In a physical environment with five disks in it, you’d be stuck with RAID 5 and that would be the performance you’d get," said Moore.
"We’re now seeing a situation where we are moving to a very dynamic storage model, where data is fluid and information flows around, both within the SAN and between different types of storage devices. This makes it available at the right time in the right place at the right cost. With virtual environments, with Compellent, with our Equallogic range and with our object storage range, we have a number of platforms that facilitate this utility or cloud model from the customer point of view."
According to Dell, technologies like virtualised deduplication open up new worlds of efficiency to companies which might previously not have been able to access them. It also acquired Ocarina in 2010, and is now incorporating its technology into its systems.
"With fluid data-in other words data that flows between different disks in the system and different platforms between systems-you can imagine that once it goes into your production SAN and gets dedup’ed, it needs to be archived and replicated for disaster recovery or business continuity purposes. But with this technology we only have to send a blueprint of the data, not the actual data itself," said Moore.
"The same goes when you want to archive that data, perhaps to our object storage platform the DX6000-you don’t have to move the full dataset, you can just move the blueprints. This capability will really explode the possibilities that cloud can offer, and I think it’s the next big step in the storage world."
Auto-tiering
With a virtualised storage environment, according to EMC’s Ward, other helpful management tools become accessible. Auto-tiering is the ability to have your storage system treat different kinds of data differently depending on the context in which it is used.
"Using this system, you can tier data in a way that’s relevant to how it’s used by the various applications. You can set policies around certain data types and applications, so for example at month’s end for a high performance banking system or an invoice processing system, you may need to have data running in flash to make it optimally available for certain processes," he said.
"That way the system can automatically tier the data for you based on historical performance, historical workloads and on how you set policies. Our fully automated storage tiering (FAST) software automatically does that. In our experience, most leading companies are saying they’re ‘cloud first’ now, meaning they’re only taking applications onsite that are cloud-enabled.
For example, we’re one of the biggest Oracle customers globally. We have 40,000 users and we’re now moving to SAP. By virtualising that and running it on our private cloud infrastructure, we’re able to speed up the whole time to market-we’ve reduced it by 60%. We’re a huge organisation, but for smaller businesses taking an off the shelf application, trying to roll it out could take nine, 12 or 14 months. Now that can be done much faster."
Through virtualisation, thin provisioning also becomes possible, allowing the IT department to tell the system that it has more storage allocated to it than it actually does.
Storage allocation
"This is conceptually allocating storage to servers that is not physically allocated-for example telling a server it has 300GB physically assigned to it when actually it only has 30GB," said Paul Hourican, chief executive officer of PFH Technology Group.
"This allows you to scale and invest in actual disk when you need it, as opposed to up front. However it’s important that companies shopping for virtualised storage do some proper research and find out exactly what vendors mean by the term. There are many variants of what is commonly termed ‘storage virtualisation,’."
"It’s important that the person buying understands what their requirements are before committing to a particular vendor, in case they later find out that they’ve actually bought less than they expected to. Storage virtualisation can offer great benefits, but like all technologies, there are no silver bullets that will solve all your problems in one go."
"That said, I do think that in the next 18 months we’re likely to see an increase in the degree of interoperability that exists from manufacturers in this area, resulting in private cloud propositions becoming more tangible and readily available. I also think we’ll see larger and faster capacity solid state hardware."
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