Speeding up your application virtualisation with Flash storage

Virtualisation has been a driving force in IT development for some years now, and this looks set to continue strongly for the foreseeable future.

A ResearchandMarkets report has predicted that there will be a compound annual growth rate of 46 per cent up to 2018 in the global client virtualisation market. This has been particularly fuelled by the growth in the cloud in the enterprise, which itself has been predicted by TheInfoPro to increase by 36 per cent year-on-year until 2016.

Contrast this to the much lower 3-4 per cent growth in overall IT spend up to 2018, according to Gartner, and it's clear that virtualisation and the cloud will be increasingly sizeable portions of the general computing budget going forward. So virtualisation will also be the area where the greatest demand for improved computing performance will be focused.

In this feature, we look at how making the right choice of storage infrastructure is a significant factor in ensuring a company's virtualisation and cloud implementations offer the best possible service.

Hard disk vs SSD

Application virtualisation is one of the most important uses for virtualisation technology. But despite the way this loads resources from a virtualised location, it will still rely heavily on very real fast disk access, because the virtualised resources will still have to be stored somewhere physically.

So overall performance will be significantly affected by storage performance, and even more so since the application won't have dedicated local storage, instead getting this from a centralised pool. In the last five years, solid-state disks (SSDs) have begun to take over from conventional hard disks. However, the latter still offer the most capacity for the money.

For this reason, hard disks remain the mass storage mainstay. But this could be a false economy when performance is crucial. Slower loading times can have a significant impact on the bottom line, and Flash-based storage may not be as prohibitive as expected, when specified wisely.

In fact, conventional hard disks simply can't deliver the millisecond or less response times demanded by some applications, making Flash-based storage the only viable option.

Hard disks are five to ten times cheaper than SSDs, with larger maximum capacities available, but they consume more than twice as much power, and have four or five times lower throughput, with 100 times slower access time.

All of this amounts to three times longer or more to transfer data in real world situations. So SSDs can significantly improve performance over conventional hard drives, which will be very noticeable when serving virtual environments.

There is a catch here, however. It's all very well having ultra-fast storage, but if the rest of the infrastructure is unable to match the performance of the underlying drives, the full benefit won't be realised. In other words, simply installing SSDs instead of hard disks into the same storage appliance will only deliver a certain level of benefit, rather than the full potential available. This is where HP's 3PAR StoreServ comes in.

HP 3PAR StoreServ

The HP 3PAR StoreServ family offers a full range of storage options, with its heritage in traditional hard disk-based arrays. However, the 3PAR StoreServ 7450 uses a different processor and memory from other members of the family to ensure it can keep up with the performance of the SSDs installed within it.

Using a quad-controller system, it can achieve 900,000 IOPS and a latency of less than 0.7 milliseconds. There's a Flash-optimised software layer incorporating HP's Adaptive technologies for read, write, and I/O processing.

The HP 3PAR StoreServ 7450 supports all three types of SSD, including premium single-level cell (SLC) drives, enterprise multi-level cell (MLC) drives and low-cost consumer-grade MLC drives. Using 920GB eMLC SSDs, a four-node 3PAR StoreServ 7450 can offer a maximum of 220TB of raw capacity, although the maximum capacity is 460.8TB using 1.92TB cMLC drives, with the latter using consumer-grade Flash memory.

Connectivity is kept flexible, with 24 Fibre Channel ports offering 8GB per second apiece, and eight 10GB Ethernet ports for iSCSI.

HP's 3PAR StoreServ 7450 can give very real benefits for virtual servers and desktops. These kinds of application are very sensitive to latency, because those accessing them will be expecting performance like a dedicated real server or local desktop.

Anything less will be perceived as a step backwards from the traditional configuration. This could give these new services the same reaction and fate of the Network Computing trend that fell somewhat flat towards the end of the 1990s.

This is unlikely to happen with virtualisation and the cloud, as both are already heavily entrenched in mainstream IT provisioning. But it's still fundamentally important that infrastructure keeps up with demand, so that virtualisation delivers on its growth predictions, without necessitating astronomical levels of investment.

HP's 3PAR StoreServe can benefit both departments greatly.

When applications don't need the performance of Flash memory, the peer-to-peer federation of HP's 3PAR StoreServ infrastructure allows data to be moved to less costly conventional hard disk space.

The Adaptive Flash Cache leverages Flash capacity from the array's SSD tier, to deliver performance when required, without needing to have an array that is entirely populated with SSDs. HP also gets the best out of its drive arrays, both in terms of capacity and performance, by utilising inline zero-detect deduplication.

Data that is merely a copy of something already held elsewhere won't need to be stored again, just a reference to the other location, which won't take significant bandwidth or drive space. So the advantage of Flash can be obtained via a mixed environment of Flash and conventional storage working together as one provision.

The growth in the importance of virtualisation across many areas of computing will put increased pressure on a company's storage infrastructure. Switching to Flash-based storage appliances holds the answer, but going over wholesale would be prohibitive.

With HP's 3PAR StoreServe 7450, in tandem with other 3PAR StoreServ appliances, a company can get the benefits of Flash storage to the level required, in a format that can integrate seamlessly with more traditional disk-based storage.

Data that doesn't need the fast throughput and access times of Flash can be kept on the lower tier. But virtualised applications can benefit from the fastest performance available, for the best possible customer experience.