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Your QLC NAND flash questions, answered

Curious about QLC NAND? From addressing capacity benefits to taking a look ahead at its uncertain future, we answer four common questions concerning the technology.

The latest evolution of NAND flash memory technology is quad-level cell NAND, and it offers significant capacity improvements over previous iterations. As its name implies, QLC NAND flash allows 4 bits of data to be stored in each memory cell. While this has given the technology a number of benefits, the increased capacity also brings complications.

NAND flash memory is used in an array of consumer devices, as well as enterprise server, storage and networking technology. It's fast, dense and relatively inexpensive when compared with other flash technologies. With QLC NAND, the medium has more capacity than ever.

Still on the fence about QLC NAND flash? Below we answer some frequently asked questions on the technology that should help clear things up. We'll cover the benefits and drawbacks of QLC, where it stands in the current market and what's expected in the future.

Is QLC NAND right for your organization?

When deciding whether QLC NAND is right for you, don't assume more capacity automatically makes it superior. A switch to QLC could be in the cards if you're looking for more capacity, and the lower cost per gigabyte is budget friendly. Your decision on whether to switch to QLC NAND often depends on what you're starting with. If single-level cell (SLC), multi-level cell (MLC) or triple-level cell (TLC) NAND options are working for you, a switch to QLC likely isn't urgent and won't offer vast improvements.

If you work with server-based, read-intensive workloads, adopting QLC technology could offer significant benefits.

However, if your organization is bogged down with aging HDDs, moving to QLC NAND flash would be a considerable upgrade. QLC NAND consumes less power than an HDD, offers better performance and will save you money on desktop hardware updates.

If you work with server-based, read-intensive workloads, adopting QLC technology could offer significant benefits. However, if your workloads are write-intensive, beware: QLC NAND suffers from poor write durability.

How does it compare to other NAND flash memory technologies?

QLC improves capacity over SLC, MLC and TLC NAND flash, but there are some issues. For one thing, the increase in capacity may be unsustainable. MLC doubles the capacity of SLC, and TLC has 33% more capacity than MLC, but QLC only provides a 25% increase over TLC. Not only are the capacity increases becoming smaller with each version, but endurance continues to suffer. The number of write cycles the drives can endure has plummeted from SLC to QLC, as the drives wear out faster.

So why on earth would you consider QLC NAND? It clearly has its drawbacks, but it's still a new technology. Workarounds, such as wear leveling and overprovisioning, are already being used to extend a drive's life. While the increase in capacity has diminished as the drives evolve, at the end of the day quad-level cell is still is a big improvement over single-cell.

Does QLC NAND fit in the enterprise?

While QLC flash struggles with endurance and performance when compared to other solid-state technologies, you shouldn't immediately dismiss its use in the enterprise. Lower costs per gigabyte make QLC a comparably affordable option in the flash market, which can be beneficial when you're buying it at an enterprise scale. Its speed leaves even the largest hybrid HDDs in the dust.

Ideal enterprise workloads for QLC NAND flash might include machine learning and data analytics, as read speeds are a strong point. Media streaming is also well-suited to QLC NAND, as high speed and capacity are required to host video files.

Where is QLC NAND headed?

There are a number of QLC NAND products already on the market, despite it being a relatively new technology. Vendors such as Micron Technology, Samsung, Intel and Adata Technology offer QLC NAND products, and given the performance and capacity improvements, the market isn't likely to slow down.

High costs are no longer a deterrent to flash technology, as prices continue to drop. This bodes well for QLC NAND and other SSDs replacing HDDs. Between QLC's density, speed, cost and power efficiency, it will be a strong contender over the next couple of years.

In addition, QLC NAND's processing power will make it a candidate for IoT and edge workloads down the line. There may not be an immediate boom in QLC NAND's popularity; it may not even see massive change in 2019. However, there's no question that the market is there for QLC NAND flash and it's going to continue to draw interest.

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