Whether you are provisioning a data center or looking for storage solutions for backup, workgroup computing, or even desktop systems, you must decide whether to use a solid-state drive (SSD) or a hard disk drive (HDD). There are arguments for deploying each type in various business settings, but SSDs are proving to be the best alternative in almost every application because of performance and reliability.
If you look at sales for computer drives over the past few years, HDDs continue to outsell SSDs, but SSDs are rapidly catching up. In 2012, the global market for HDDs was 475.4 million units as opposed to 31.1 million SSDs. In 2015, there are expected to be 416.7 million HDDs shipped in comparison with 153.8 million SSDs. And by 2017, the market is expected to ship 409.9 million HDDs and 227.1 million SSDs.
Shipments of HDDs remain strong because of their price. Enterprise Storage Forum determined that the price for SSDs varied from $1,000 to $5,000 per GB per second, whereas enterprise HDDs were running around $1,200 per GB per second. Clearly, the price/performance of SDDs is catching up with HDDs, and when you factor in the additional benefits of using SSDs in business-critical computer settings, SSDs will win out as a better enterprise investment. Here is a brief HDD versus SSD comparison for business users:
First, SSDs are faster than HDDs, which are mechanical and therefore limited by having to physically scan the hard drive for disk reads/writes. The maximum speed an HDD can achieve is 15 RPM, and even at that speed it can create a bottleneck for a high-traffic environment. You can offset some of that limitation with parallel disks, caching, and more RAM, but eventually performance will top out. And adding all that extra memory and caching makes HDDs more expensive than SSDs for enterprise applications.
SSDs outperform HDDs in almost all areas. They deliver 100 times faster performance with almost instantaneous data access because there are no mechanical processes, read/write heads, or seek limits. In fact, SSDs provide instant access to data located anywhere on the drive. SSDs also deliver faster file transfer rates and faster boot times.
The difference in performance comes from the way data is accessed on SSDs versus HDDs. In high IO environments, SDDs will perform faster. The storage operating system handles IO read and write requests, but with an HDD, those requests are to a physical disk location; the platter spins and the head has to find the physical location, and if read/write requests are non-contiguous, it means more latency. With SSDs, there are no physical disk locations so IO requests are faster, which is ideal for high IO environments such as data warehouses.
HDDs are mechanical and, therefore, subject to mechanical failure. Moving parts will fail over time. Furthermore, the physical surface of the disk drive itself can wear with time. However, in a data center setting, HDDs can be useful for protecting data center data and can be more reliable than SSDs in some cases.
Because they use non-mechanical, NAND-based flash memory, SSDs are more versatile for tough environments and better able to handle a shock or dirty environments. However, for data center applications in which the environment is controlled, SSDs and HDDs are on a par in terms of reliability.
SSDs also are subject to hardware failures, such as transistors or capacitors. Even firmware can fail. In the case of DRAM SSDs, a power outage will mean that capacitors will fail quickly, and if the data has not been protected or stored, it will be lost—which is not an issue with a physical storage medium such as a magnetic HDD. SSDs age more slowly, but performance will degrade with age. Reads and writes will wear out memory cells over time.
So for data center applications, saying which type of drive is more reliable is difficult. Each has its own strengths and weaknesses, although more data centers are adopting SSDs to gain better performance, which can mean everything in some business applications.
SSDs bring other advantages to the data center such as lower power, heat, and noise.
Because they use flash memory rather than mechanical read/writes, SSDs use less power especially at peak loads. An SSD will use about 2W at peak, whereas an HDD will use about 6W. Lower power usage could mean lower utility bills depending on the size of the storage system, and for battery-operated systems, such as notebooks, it means longer battery life.
Lower power also means less heat. No cooling is required for SSDs, which means less heat in the data center and less demand for cooling.
And then there’s noise. Granted, HDDs aren’t particularly noisy, but when you assemble a number of them in the same location, the mechanics and cooling that goes with it can make for a noisy environment. SSDs are silent and can reduce noise pollution in the data center.
So which type of drive systems is best for business users? SSDs offer a number of advantages over HDDs, and when you assess overall operating costs, you’ll find they are comparable or even less. HDDs will continue to have value for non-critical computing and data backups, but for high-speed performance for business-critical computing, businesses find that SSDs can really deliver.