Solid State Drives (SSDs) have become more and more prevalent over the years and are starting to become the norm for home computing devices. They are also now used extensively in enterprise-class systems that rely on data storage that is not only reliable, but able to maintain high data read/write speeds as well.
However, as the demand for better performance and reliability increases, so does the need for more modern technology that can keep up with today’s computing requirements. Until now, the most common types of SSD drives would have relied on SATA and SAS connection protocols, but the introduction of newer technologies could overturn them as the industry standard options.
In this post we’ll take a look at the difference between SATA and SAS and understand the reasons why the data storage industry is moving away from using these interfaces. We’ll also find out more about PCIe and NVMe technologies that are driving this change and taking us to a new era of SSD performance.
How do SATA and SAS work?
Let’s start with a few basics around SATA and SAS. Serial Advanced Technology Attachment (more commonly referred to as SATA) is a type of hardware interface that allows the transfer of data to and from HDDs and SSDs. SATA SSDs are adequate for the majority of home uses as they are generally cheaper, operate at a lower speed and have a lower write life.
Whilst fine for everyday computing, in a RAID server array or data centre environment often a better alternative has been to use ‘SAS’ drives, which stands for Serial Attached SCSI. This is another type of interface that, again, can be used either with HDDs or SSDs. ‘SCSI’ stands for Small Computer System Interface (which is why SAS drives are sometimes referred to as ‘scuzzy’ drives). SAS has increased IOPS (Inputs Outputs Per Second) over SATA, meaning it has the ability to read and write data faster. This has made SAS an optimal choice for systems that require high performance and availability.
On an enterprise level, SAS prevails over SATA, as SAS has more over-provisioning to prolong write life and has been specifically designed to run in environments that require constant drive usage.
The introduction of PCIe and NVMe
The latest developments in solid state technology have taken a giant leap forward in comparison to SATA and SAS, and are surpassing the current performance standards of NAND flash-based devices. The introduction of PCIe has taken over SATA as a high bandwidth data transfer interface not only in home computing but also for enterprise-level hardware. PCIe (Peripheral Component Interconnect Express) is a high speed serial computer expansion bus standard and can offer drastically higher data transfer rates over SATA or SAS interfaces due to the fact that there are more channels available that allow the flow of data.
PCIe is being adopted by many of the leading drive manufacturers as the standard for new home and enterprise storage and some peripherals. For example, you’ll see that the the latest Apple Macbooks ship with PCIe-based flash storage, something that Apple has been adopting over the years with their consumer devices. PCIe can also be used within data centers for RAID systems and to create high-speed networking capabilities, increasing overall performance.
NVMe and pricing differences
The latest PCIe solid state devices are using NVMe (Non-Volatile Memory Host Controller Interface Specification). This is a logical interface that allows the PCIe bus to access flash storage devices. The combination of PCIe/NVMe provides the capability for SSDs to get past the limited data transfer speeds that traditionally plagued SATA SSD connections, which were originally designed for use with HDDs. You’ll need to pay for the premium though; a Samsung 950 PRO NVMe M.2 256GB SSD will set you back around £300 at the time of writing, whereas the 2.5 inch SATA III equivalent (like the Samsung 850 PRO in the picture above) is a little more than half the price.
The advertised differences in performance when using PCIe/NVMe SSDs over SATA and SAS SSDs are significant, with average sequential read/write speeds being much faster. However, in real-world PC situations you’re likely to only see differences in actual performance upon booting your system or when loading programs.
The future of SSDs
SATA SSDs will still technically have their place as higher capacity flash storage for the foreseeable future; however if speed isn’t a priority any HDD will continue to be a cost-effective alternative with their low cost-per-gigabyte. There are many new technologies hitting the market for SSD storage, including M.2 PCIe SSDs which offer vastly increased performance and are widely cited to be the new standard for the consumer laptop market in 2017. In addition, NVMe is replacing SAS SSDs for enterprise-grade/performance-based IT, given their vastly increased performance.
Looking at SSD storage objectively, like most things in IT; the application and use case will determine the best choice of technology when it comes to data storage. It’s also worth mentioning that any type of SSD can experience data loss as a result of physical component failure or logical failure, therefore be sure to revise your disaster recovery plan if you decide to use a new type of storage media. Ideally, you’ll also want to include contact details for a data recovery professional who has experience in recovering data from the latest advancements in SSD technology.
What types of SSDs do you use, personally and professionally? Do you run applications or systems that use NVMe? Let us know by tweeting @DrDataRecovery.
Mikey has been with Ontrack for 6 years and is the Partner Program Manager, based out of the Epsom, UK office. He is a regular contributor to the Ontrack blog, usually writing about how different types of data storage technologies work. Outside of work you’ll find him either with a guitar in his hands or learning about rocket science.