Myth or Fact: Flash Storage Tradeoffs

By Neeraj Gokhale

Myth or fact? In flash storage, you can have performance, affordability, or enterprise-grade resiliency and data services, but you can’t have all three.

It’s pretty much the accepted wisdom in IT organizations that if you want something “faster, better and cheaper,” you’ll end up disappointed. It’s possible to achieve one or sometimes two of these characteristics, but almost always at the expense of the third. It’s called the Iron Triangle, and program managers make their living balancing these demands and mitigating the tradeoffs that almost inevitably result.

One school of thought says the same is true in the flash storage world: you can have performance, affordability, or enterprise-grade resiliency and data services, but you can’t have all three. But is that really true, or is it a myth perpetuated by storage vendors to cover gaps in their product offerings?

Flash Storage Benefits

The primary appeal of flash storage is performance—solid-state arrays provide performance levels an order of magnitude faster than disk-based arrays. How much faster? A high-performance 15,000RPM spinning-disk drive can perform at best a few hundred IOPS at 3–4ms latency. A high-density flash drive can perform thousands with sub-millisecond latency. A fully populated high-density array can deliver in excess of one million IOPS while maintaining that sub-millisecond latency.

So it’s pretty much a given that flash solutions will deliver performance, and many of them can do it at an acquisition cost similar to that of high-performance 15,000RPM spinning disks. In fact, the right configuration of high-density flash can be had for as little as $1.50/GB of useable storage.

Flash provides additional cost benefits. Enterprise IT commonly overprovisions disk storage silos to boost performance. The speed of flash eliminates the need for overprovisioning. Flash performance also provides benefits on the server side, reducing wait times and allowing applications to run more efficiently. Applications can run on fewer CPU cores, reducing hardware, software licensing and maintenance costs. Flash arrays can also reduce storage footprint by as much as 80 percent, with corresponding reductions in power and cooling costs.

A recent Wikibon study proved these benefits, achieving a 75 percent overall read/write performance improvement and up to 6x reduction in latency by upgrading an existing Oracle OLTP application with flash storage instead of Tier One disk storage. Wikibon found additional benefits, including the ability to accommodate more users, enable developers ready access to full database copies and provide significantly faster report generation. It found the total cost of ownership (TCO) of upgrading to flash to be a fraction of the TCO of upgrading to Tier One disk.[1]

Wikibon found that as latencies dropped, server wait times also dropped, allowing for substantial core-count reductions and yielding a 60 percent reduction in Oracle licensing and maintenance costs and a 50 percent reduction in the three-year database delivery costs for the sample in their study.[2]

The industry has recognized these performance and cost factors, and we’re now seeing flash go through the classic technology-adoption curve as enterprises shift from 15,000RPM disk drives to flash for high-performance applications. Flash will continue to become more affordable, with at least one industry analyst predicting that by 2017, the effective cost of deploying it in the data center will be lower compared with spinning disk and that the cost benefit will increase rapidly over time.[3]

But there’s a catch. The affordability of flash is directly related to the use of in-line data-reduction techniques like deduplication and compression. These techniques can easily provide compaction ratios of 4:1 to 6:1 and are the key to achieving the benefits of flash storage in the enterprise.

Unfortunately, data reduction is not a standard feature on many flash arrays—it’s often provided either through an external appliance, which can increase cost, or through software, which can reduce application performance. And when it comes to the third side of the triangle—resiliency and data services—most vendors can only dream of providing the massively parallel architectures and Tier One data services like transparent failover and synchronous/asynchronous replication that you’ve come to take for granted with spinning disk.

A Faster, Better, Cheaper Solution

If you know what you’re looking for, you can find flash storage that meets all three criteria—faster, better and cheaper. When shopping for flash storage, make sure you’re getting the whole package. Look for flash arrays that provide the following:

  • Scalability to the petabyte level
  • High-density drives (3.84TB SSDs) to minimize floor space and power requirements
  • Performance up to or more than one million IOPS at sub-millisecond latency for a fully loaded array
  • A price similar to or lower than 15,000RPM spinning disk (as low as $1.50/GB useable storage)
  • Hardware ASICs that offload processing such as deduplication and compression from servers/controllers, giving these components more bandwidth to perform their primary functions
  • A mature and massively parallel storage architecture that performs well under failure conditions and provides proven six-nines availability
  • Tier One data services that guarantee resiliency
  • Data protection that allows you to combine the best of snapshot replication with off-array backup and archival
  • Storage federation that allows you to pool multiple flash arrays together

All of this adds up to a flash storage solution that gives you all of the features you’re looking for without tradeoffs. It’s a fact, not a myth. No more hard decisions about what to give up to get the performance of flash. Many vendors will try to sell you something less, but don’t be fooled. You can have flash storage that provides the best in performance, affordability, and resiliency and data services.

[1] Based on unpublished research performed by Wikibon and commissioned by HPE, December 2015.

[2] Based on internal HPE testing completed in November 2015.

[3] Wikibon, The IT Benefits of an All-Flash Data Center, David Foyer, 23 March 2015, http://wikibon.com/the-it-benefits-of-an-all-flash-data-center/

 

This article appeared first at datacenterjournal.com  on 02/22/2016 and was reposted by Your Daily Tech with permission by the author.