All-Flash storage seems to be taking over the industry by storm. Yet, there are still a number of IT Professionals hesitant about making the switch to this higher performing, more reliable form of data storage. Why is this? Is it the cost? Is it the fact that IT Pros are so comfortable with the tried and true spinning disk forms of SAN storage and they’re afraid to move to a new platform? Or is it because they are skeptical of SSD lifespans? Well it depends on the individual, but almost IT Admins have thought about these questions at one point or another.
Spinning-disk SAN storage has been around for a number of years, and for those of us who have been in the storage industry for a while, this is what we’re familiar with. In many cases, spinning disk storage does just enough to get the job done. Spinning drives are fine for IT environments that do not require a high performing array. Let’s say you don’t have high performing applications, you aren’t utilizing VDI, or you’re just using a storage system for disaster recovery purposes. In these use cases, you probably don’t need something as high performing as a Hybrid or All-Flash Array. But if you have I/O intensive applications and are dealing with performance issues, you’re going to want to look at an SSD based storage array that will provide you with the performance necessary to have a prosperous IT environment. This comes in two forms. You can look at a hybrid unit, which consists of SSDs and spinning drives. The SSDs host the high performing applications, and the spinning drives host the non-I/O intensive applications. Or if you want the highest performance possible, you can look at an All-Flash array. This type of unit is comprised solely of SSDs. An All-Flash array is going to be the highest performing unit on the market, and you are really going to be able to get the most bang for your buck out of SSDs with this type of storage array.
If you have high performing applications, or are looking at a VDI implementation, All-Flash storage needs to be considered, possibly even required. So what type of performance metric should you look for to ensure that you have a high performing array? Back in the spinning disk era, performance was largely measured by IOPS. IT professionals were constantly looking at how many IOPS they could achieve. In order to get the most IOPS, folks would often add as many spindles to the unit as they could, and would purchase higher performing drives. For example, 15K RPM drives as opposed to those pesky 7.2K RPM drives. This worked great for a while, however once SSDs started becoming more and more affordable, we saw a number of storage vendors implementing SSDs within their storage arrays. Once this started happening, we discovered that IOPS were not much of a concern anymore, and quickly realized that latency was the new proper performance metric. The reason being is that you can get upwards of 30,000 IOPS out of one single SSD drive. Just imagine what happens when you place a handful of these drives into a storage array…It’s clear that IOPS is no longer going to be a concern when comparing SSDs to spinning drives.
Are SSDs Going to Last?
So why would someone not want to move to this high performing form of SAN storage? One of the most common misconceptions of All-Flash storage, and more specifically SSDs, is that they’re not going to last. When SSDs first came to market there was a concern around the lifespan of SSDs. While spinning drives are mechanical in nature, SSDs are not. Instead, an SSD’s lifespan is based off of P/E cycles. This stands for program-erase cycles. A P/E cycle is the order of events in which data is written to a flash memory cell, then erased, and then rewritten. The number of P/E cycles is limited on SSDs, and people are often hesitant because of this. However, there should be very little worry here. As opposed to spinning drives which are mechanical in nature and can fail randomly without you being notified, with SSDs we are able to predict when the SSD is going fail, and you are able to proactively replace this drive prior to the actual failure. Additionally, failures do not happen nearly as often as some may think. Currently we see SSDs lasting an average of about five years or so. Obviously this number varies based on how you leverage the SSDs. Certain technologies such as caching and tiering can help increase the longevity of these types of drives, and it’s important to ask your storage provider how they will help you maximize the longevity of your SSDs. Also, if your storage provider can provide an SSD endurance guarantee for “X” number of years, that’s something you should keep an eye on as well.
Afraid of Change?
Another reason some IT Pros are hesitant to move toward All-Flash is because they’re afraid of change. Sure, an all SSD storage array may bring you higher performance, but you’re used to spinning disk or hybrid storage, why would you switch from something you’re so familiar with? In many cases, this is because you have to. Many applications today require All-Flash performance. VDI environments and various other types of applications require high performance storage, and you’re not able to squeak by with having spinning drives in your storage system. All-Flash solutions are going to make your environment much more effective, and if you give it the chance, All-Flash storage could be a game changer for your infrastructure. For example, rather than seeing around 20-25 ms of latency with an all spinning disk solution or 5-10 ms of latency with a Hybrid Array, with an All-Flash Array you will typically see sub 1ms of latency. Performance issues solved!