{"id":289,"date":"2020-03-26T13:19:58","date_gmt":"2020-03-26T11:19:58","guid":{"rendered":"https:\/\/tekmart.co.za\/t-blog\/?p=289"},"modified":"2020-03-26T13:19:59","modified_gmt":"2020-03-26T11:19:59","slug":"the-pros-and-cons-of-flash-memory-revealed","status":"publish","type":"post","link":"https:\/\/tekmart.co.za\/t-blog\/the-pros-and-cons-of-flash-memory-revealed\/","title":{"rendered":"The pros and cons of flash memory revealed"},"content":{"rendered":"Reading Time-approximately:<\/span> 4<\/span> minutes<\/span><\/span>\n

Flash memory and solid-state devices have revolutionized storage, but to deploy them effectively you must understand what they can and can’t do. Find out what you need to know.<\/strong><\/h2>\n\n\n\n

By <\/p>\n\n\n\n

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Rich Castagna<\/strong><\/p>\n\n\n\n

Vice President of Editorial – TechTarget – SearchStorage<\/a> <\/strong><\/p>\n\n\n\n

\t\n\t\n\tPublished: 18 Mar 2020<\/a><\/p>\n\n\n\n

Solid-state storage, built on a foundation of NAND flash memory \ntechnology, has radically altered the look of enterprise and personal \nstorage infrastructure in little more than a decade. Flash shook up a \nstodgy storage market that was beginning to feel the burden of \ntechnology developed back during Eisenhower’s first term. Since \nsolid-state came on the scene, stacking platters to create more capacity\n and short stroking<\/a> to pump up performance now seem like desperate attempts to squeeze just a bit more out of spinning disk gear.<\/p>\n\n\n\n

Some pros and cons of flash memory were evident from the beginning. \nThe first SSDs were far faster than any hard disk drive (HDD) available,\n but they had limited capacities and sticker-shock-inducing price tags. \nThat situation didn’t last long, as NAND flash technologies quickly \nevolved and the industry overcame many of flash memory’s initial \nshortcomings. However, there still are some important factors to \nconsider when deciding between solid-state or spinning-disk storage — \nor even a combination of the two.<\/p>\n\n\n\n

Advantages of flash memory storage<\/strong><\/h3>\n\n\n\n

As its name implies, flash storage is fast<\/a>\n — very fast — when compared to traditional magnetic media. Depending \non the criteria used to measure performance — throughput, IOPS or \nlatency — solid state tops hard drives by multiples ranging from two or\n three times to differences measured in orders of magnitude.<\/p>\n\n\n\n

While flash’s throughput<\/a>,\n which is typically measured in megabytes, can easily top that of HDDs, \nother SSD performance stats are far more impressive. For example, \ndepending on the data block size, a speedy HDD might clock up to 200 \nIOPS, while a solid-state drive’s IOPS might be measured in the tens of \nthousands. So, if speed’s your need, flash is the clear choice.<\/p>\n\n\n\n

Some of flash storage’s physical characteristics also give it an edge over hard drives. Flash drives are likely to be more durable than hard drives, as they don’t have any moving parts compared to highly mechanical HDDs that have stacks of spinning platters and read\/write heads traversing those disks. Without motors, actuators and heavy platters, solid-state storage units are lighter than HDDs and use far less electricity and, therefore, produce less heat than hard drives.<\/p>\n\n\n\n

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SSDs are often packaged to fit drive bays intended for hard drives, \nbut that’s just for convenience when using standard interfaces initially\n intended for HDDs. Newer flash form factors can package the same, or \nmore, capacity in much smaller units, so less space is needed to \naccommodate petabytes of storage in data center racks.<\/p>\n\n\n\n

Despite all the moving parts, hard drive technologies have continually improved<\/a>\n over their nearly 70-year lifespan to achieve impressive levels of \ndependability and durability. Still, flash memory beats or exceeds HDD \nreliability and endurance and, with no moving parts to jar, flash is far\n more reliable for use in mobile devices.<\/p>\n\n\n\n

Disadvantages of flash memory storage<\/strong><\/h3>\n\n\n\n

It’s fast, it’s small and light, and it barely sips from the power \nsupply — it’s hard to imagine any shortcomings when assessing the pros \nand cons of flash memory. For sure, there aren’t many disadvantages, but\n one significant issue is its cost<\/a>. On a capacity basis, flash storage costs five to eight times the price of a comparable-capacity HDD.<\/p>\n\n\n\n

That multiple has come down significantly over the years, but \nclearly, all the advantages of flash memory storage come at a price. In \ncertain implementations, the cost difference may nearly disappear, \nparticularly if you’re using flash drives to replace a bunch of \nshort-stroked, low-capacity 10K rpm hard drives in a \nperformance-oriented array. A handful of SSDs may be able to produce the\n same or better performance without the waste and expense that short \nstroking entails.\n \n \n Flash memory beats or exceeds HDD reliability and endurance and, \nwith no moving parts to jar, flash is far more reliable for use in \nmobile devices.\n \n \n \n <\/p>\n\n\n\n

It’s important to note that NAND flash prices have steadily declined\n and are likely to continue to do so. They may never be as cheap as \nspinning disk, but as the price delta narrows, their advantages will \nloom even larger.<\/p>\n\n\n\n

Another knock against flash memory storage is its inability to hold \nup under heavy write loads. Similar to hard drives, repeated use will eventually degrade SSDs<\/a>.\n With HDDs, writing new data over deleted data is a simpler process \nbecause the drive doesn’t delete the old data; it just makes space \navailable for new writes. With NAND flash drives, the old data must be \nremoved first before the new bits can be dropped in the cells in a \nprocess called program\/erase. That slows down writes and increases wear \nand tear. This issue has been addressed in a variety of ways with \ntechniques that reduce the number of processes needed to reclaim cells \nfor new writes.<\/p>\n\n\n\n

Another endurance issue<\/a>\n is linked to the architecture of NAND flash. The earliest solid-state \ndrives stored a single bit of data in each flash cell; that resulted in \nspeedy, long-lasting and expensive flash storage. Since then, the number\n of bits per cell has risen steadily, and today, triple-level cell with \nthree bits per cell and quad-level cell (QLC) with four bits per cell \nare the norm. These newer generations of NAND enable greater capacities \nand lower prices per GB, but they also slow operations and increase the \nchances that a bit in one cell may affect data in an adjoining cell. \nAgain, controller technologies have been developed to address these \nissues, and flash memory endurance is continually improving.<\/p>\n\n\n\n

Earlier flash memory drives offered far less capacity than hard \ndisks, so they were relegated to handling specific high-performance \nfunctions that didn’t require a lot of capacity. But with flash \ntechnologies such as QLC and 3D NAND, where cells on NAND chips are \nstacked in tiers on top of each other, capacities for SSDs have risen \nsteadily and are now competitive with HDDs.<\/p>\n\n\n\n

Best of both worlds<\/strong><\/h3>\n\n\n\n

SSDs’ falling prices and rising capacities have made them ubiquitous\n in everything from enterprise arrays to servers to laptop PCs. But hard\n disks still have a place, particularly for secondary storage \napplications such as backup and archiving. And while all-flash arrays<\/a>\n have carved out a chunk of the enterprise market, there are still \nplenty of applications that can benefit from a hybrid environment where \nhigh-performance solid-state storage is paired with high-capacity — and\n inexpensive — hard disks.<\/p>\n\n\n\n

Next Steps<\/strong><\/h4>\n\n\n\n