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Maximizing SSD ROI

By Paul Rubens

Ensuring SSD return on investment (ROI) is enabled by using a portfolio management approach. SSD ROI is always dependent on finding the correct role for flash in your data storage setup.

SSD benefits can be substantial, but keep this in mind: an investment in high speed solid state drives (SSDs) is just like any other investment -- it should be carried out with a view to maximizing the return on investment (ROI).

When you look at it like that the decisions about whether to invest in SSDs, how much SSD storage to buy, and where to deploy it become much easier:  it becomes a matter of working out what course of action maximizes your SSD ROI. One way to do this is to think about investing in SSDs in the context of a portfolio.

 A financial portfolio will often contain a mixture of cash, stocks and bonds, and its exact make up will depend on the investor’s attitude to risk versus return, as well as the need for income and other factors.

You can think of an enterprise's storage portfolio as something similar: it will usually consist of some combination of tape, hard disk drive (hdd) and SSD storage, and its exact make up will depend on the enterprise's need for storage capacity and the storage requirements of the applications it runs.

But, crucially, the makeup of an enterprise's storage portfolio  also depends on the financial resources it has at its disposal. That's because if the storage budget were unlimited (or, put another way, if all storage was free to buy and operate) then running an all SSD environment would be a no-brainer.

Software defined storage key to SSD Benefits

So going back to a financial portfolio, one of the key decisions an investment manager needs to make is about asset allocation. What that comes down to is this: how much of the portfolio should be allocated to stocks, how much to bonds, and how much left in cash. Each asset class has its own risk and return characteristics, and changing the mix of three types of assets effects the risk and return profile of the portfolio as a whole.

Something similar is true with a storage portfolio. One of the key decisions you need to make is how much storage should be allocated to SSD, how much to HDD and how much to tape. Each storage medium has its own performance and cost characteristics, and the mix of each storage type effects the profile for the storage portfolio as a whole.

To maximize your SSD ROI you need the flexibility to change your asset allocation as your requirements, prices and the performance of storage devices change, and the way to get that is through software defined storage (SDS), according to Mark Lewis, a former CTO of EMC and GM of HP Storage who is now CEO of storage software startup Formation Data Systems.

He argues that SDS provides the storage agility required to add SSD resources to whichever applications can benefit from them the most at any given time – helping to maximize SSD ROI – and since SSDs can be installed in commodity hardware (rather than specialized arrays) that also helps improve SSD ROI.

In fact it is SDS that enables storage to be treated as a single portfolio (or "pool") of different storage assets rather than as a collection of disparate and sometimes incompatible devices.

For companies yet to invest in SSDs, Lewis adds that software defined storage can also help SSD ROI by insulating buyers from the need to deal with new vendors selling hardware that may be incompatible with their existing storage systems.

"Flash shouldn't be disruptive because it is just a new technological development and a good storage architecture should make that transparent," he says. "So with software defined storage there is no discontinuity – you don't need to deal with new vendors and learn to use new hardware to take advantage of flash."

Internal markets to boost SSD ROI

Before you can tackle the problem of storage asset  allocation you need to have a clear idea of the monetary value to your organization of better storage performance for specific applications.

Let's go into the issue in a little more detail. It may be desirable for a particular application to run on faster storage. But unless you can articulate how desirable that is by figuring out what the financial benefit would be over a fixed timeframe –  if the storage performance were  x% faster or y% faster – you can't calculate whether it is worth making the investment in SSDs needed to achieve an x% or y% performance gain.

The other side of the equation is the amount that needs to be invested in SSDs over that time frame to achieve an x% or y% performance gain. It's only then that you can calculate SSD ROI. The cost of SSDs themselves is obviously important, but the total cost of ownership (TCO) over the time period is actually what's relevant. This includes the purchase cost of the SSDs themselves, but other factors that need to be taken in to account include:

·  Power consumption – SSDs consume less power and require less cooling than HDDs, and a relatively small number of individual SSDs may replace a large number of short-stroked HDDs.

·  Array or other enclosure costs – SDDs have tended to be lower capacity than HDDs in the past, resulting in higher rack space requirements per gigabyte stored than HDDs unless short stroking is being employed. (That is becoming less of an issue because SSDs now have capacities on a par with HDDs, although they are very expensive.)

·  Warranty costs (see below)

·  Savings from reallocating HDDs – drives that have been replaced by SDDs can sometimes be redeployed to other storage duties, obviating the need to purchase new disks. (It's worth noting that if HDDs have been short stroked to provide higher performance then the storage capacity that has been freed up will be magnified if the drives are subsequently deployed without short stroking.)

Jim Handy, an analyst at Objective Analysis, points out that the Storage Networking Industry Association (SNIA) has a useful tool dating back to 2009 that can help you work out which of your applications can get you the biggest SSD ROI.)

SSD ROI and timing

Another factor to think about when looking to maximize SSD ROI is when to make an SSD investment. With a financial portfolio you look to make investments when prices are weak, but with the expectation that they will rise. But SSD storage prices fall over time, so in theory the longer you delay making SSD purchases the lower the cost, and therefore the higher your SSD ROI.

The problem is that you don't get any SSD ROI at all if you don't make the investment at some point. That means there's no point in delaying purchases indefinitely to take advantage of falling prices, but it is worth watching the market to take advantage of any temporary price weakness. This could be caused by a supply glut or the end of a product's lifecycle.

You may decide to make SSD investments to coincide with the end of life of existing storage systems. If you are replacing HDDs then your hands will be tied to a certain extent because their proclivity to fail is a function of age and at a certain point they will need replacing.

But if you are investing in SSDs to replace existing SSDs then the story is somewhat different and you can increase the SSD ROI you get from your existing SSDs by keeping them in service for longer.

That's because SSDs' proclivity to fail is a function of use, not age, and thanks to SSD monitoring capabilities you can get an accurate picture of how much your SSDs have been used and how much life they have left in them, says Mark Peters, a senior analyst at Enterprise Strategy Group. "SSDs have an elegant death, so you can manage and plan around that," he says.

He adds that manufacturer warranties can help ensure that the SSD ROI you get is not lower than you expect due to early failures, and anecdotal evidence suggests that vendors are not having problems with the guarantees they issue. That  implies that enterprise SSDs are at least as reliable as had been expected by the vendors.

SSD ROI depends on what you buy

In financial investment management once you've decided on asset allocation you also have to make decisions around stock selection: which individual companies do you invest in? When it comes to storage this becomes a question of which SSDs should you buy.

"All flash is not the same, but many people seem to forget this," says Peters. "There is fast flash and less fast flash – just as there are fast and less fast disks."

What this means is that as well as choosing between HDD and SDD, you also have a choice between faster (and presumably more expensive) SDDs, and slower, cheaper ones. And longer lasting ones (backed by a vendor guarantee) or less reliable but less expensive ones.

To maximize SSD ROI it's not necessarily the case that you should choose one particular make and model of SSD. That's because by mixing attributes and costs you are more likely to get the exact blend of cost, reliability and performance that you need to maximize SSD ROI.

"Having a blend of SSDs will certainly make sense for some organizations," Peters says.

Loops and delays affect SSD ROI

Can Peters offer any other tips for companies to help them maximize their SSD ROI? It turns out that he does have one more. It concerns older applications that some organizations have developed themselves for internal use.

 "These applications are often the center piece of the business, and some were written with loops and delays in them to make them wait for (slower) disks," he says. "To get the SSD ROI that you expect you many need to look at rewriting these  applications – otherwise you may find that you can't actually benefit from the SSDs that you buy."




  This article was originally published on Tuesday May 17th 2016
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