The hard disk drive has been around since 1956 and has been the dominant long-term storage medium since the '60s. That's all changing now, at least for businesses. With recent advances in flash storage arrays, many IT professionals are starting to realize that the benefits of flash far outweigh the value of their current hard disk file servers. Falling prices for flash storage coupled with incredible advances in dedupe, compression, provisioning and parity make it a viable alternative to clunkier, slower storage options.
What is a Flash Array?
An all-flash storage array is a combination of an array controller — that manages array resources, implements RAID and operates failovers — and an enclosure of multiple, hot-swappable solid state drives (SSDs). Solid state memory has a finite lifespan. Each drive can write to each of its sectors a limited number of times before the drive starts to fail. In a desktop drive, there's not much you can do to manage writes, but a flash array controller can spread writes out across all sectors on a disk and across all disks in the array, giving flash arrays longevity similar to hard disk storage. In order for flash arrays to feature storage capacities similar to hard disk arrays, they have to be able to reduce the raw data they store. Fortunately, they can do just that.
By combining technologies like compression, deduplication, pattern removal and thin provisioning, many flash storage arrays reduce physical data size to as low as one-tenth the logical size. This allows flash arrays to compete with hard disk arrays on a dollar-per-gigabyte level. Comparing hardware prices isn't enough, however. For any business that relies on its IT infrastructure, the amount of time a transaction takes can mean a huge difference for revenue.
Hard drives are mechanical devices and, because of this, work most efficiently when they read and write data sequentially. When your information is stored on a disk spinning between 7,200 rpm to 15,000 rpm, jumping from place to place to access data can cause read/write times to skyrocket. SSDs, however, are purely electronic. Because they don't rely on mechanical components, they're able to deliver consistent results, regardless of what data they're accessing. This means that access times for solid state arrays can be up to one-tenth the times hard drive arrays require.
What Kind of I/O Does Flash Deliver?
Modern flash arrays can consistently deliver 100,000 IOPS with latencies below 1ms. If you're considering deploying a VDI at your company and want to support several thousand users, an all-flash array can erase your fears of boot storms destroying morning productivity. The low latencies flash delivers can get everyone up and running without any detectable performance impact. Not only that, but you can reduce storage provisioning for virtual desktops and servers from several minutes to 50 seconds or less. You can update thousands of virtual desktop images while your coffee's brewing rather than having it take up your whole lunch break.
Just a few years ago, flash storage was just a way to boost the performance of hard drives and as a tool for individual consumers to speed up their computers. Now, however, businesses are able to use all-flash arrays to reduce latency and increase IO all without spending more than they would for hard drive arrays. It's hard to doubt the utility of flash storage and we've reached a tipping point where hard drives will finally fall out of favor.
Action Item: Carefully consider your business server storage options. Falling prices for flash storage coupled with incredible advances in dedupe, compression, provisioning and parity make it a viable alternative to clunkier, slower storage options.
Amy - thanks for the posts. Here are some Wikibon research articles that go into detail on architectural and financial analysis of flash solutions.