SSDs have reliability edge over hard drisk drives (HDD)

A recent report from Data Center Knowledge analyzes the reliability of hard disk drives, and compares them to solid state disks. According to the report, solid state drives are widely considered more reliable, but recent hard disk drive releases are putting this conclusion in to question because they have displayed incredibly reliable construction. Overall, the report said the best way to tell which is more reliable is to understand why drives fail.

According to Google's disk failure experience report, just 36 percent of hard disk drive failures were experienced for reasons that cannot be identified through SMART disk monitoring. Data Center Knowledge said SMART monitoring systems use self-monitoring, analysis and reporting systems to identify if a hard disk drive is about to fail.

HDDs can fail in two ways — electronic and mechanical. SMART disk monitoring data can track mechanical failures. According to the report, hard disk drive mechanical failures are, to a certain extent, inevitable, because of the moving parts involved in making a hard disk drive work. An HDD features motors, spindles, platters and actuators that are all precisely aligned to make an HDD work. Over time, those components can begin to wear, causing the device's eventual failure. This is the type of failure that SMART monitoring can anticipate.

However, the report said SMART systems cannot anticipate electrical causes for failure. These issues can be created by broken capacitors, poor power regulation and problems connected to the firmware or power connection system. Since Google estimates approximately 36 percent of failures are not connected to smart monitoring, the report concludes 36 percent of HDD failures are related to electricity.

For a solid state disk drive, the same mechanical failures associated with HDDs are not possible. SDDs do not have any moving parts because they use flash memory. As a result, just 36 percent of HDD failure types are even relevant to SDDs. However, the report said the quality of the flash memory chip used in SSDs can have a drastic impact on their ability to run without failure.

Currently, the report said the SSD market is relatively young, and there is currently a great deal of variety in the quality of flash chips available. While leading manufacturers use high-quality chips in their SSDs, and send lower types of flash to be used in thumb drives and memory cards, growth in the entire market is not as consistent.

In many ways, this is reminiscent of where the HDD market was when that technology was young, the report said. About 15 years ago, HDDs were built with significant mechanical diversity, with high-end models proving reliable, but others being more risky. As a result, failure was more likely. Currently, the HDD market is sophisticated, and almost all devices are mechanically optimized, according to the report.

Overall, the report supports the theoretical advantage of SSDs because they will experience fewer opportunities to fail. As a result, the report estimates an SSD will have a 30 to 40 percent less chance of failing over a five year period than an HDD.

Because SSDs are relatively young in their product lifecycle, a high-capacity SDD is significantly more expensive than a similar HDD. However, many desktop computer users are taking advantage of the SSDs' reliability and speeds, while still using an HDD for primary storage. This can be achieved by upgrading your computer with a dual-hard drive configuration. In this instance, a lower capacity SSD is used as a boot drive. It will hold the operating systems and any other major applications that you use frequently. Other data, such as secondary applications and assorted files, get stored in the HDD where more space is available.


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