{"id":6935,"date":"2021-05-28T11:34:32","date_gmt":"2021-05-28T09:34:32","guid":{"rendered":"https:\/\/tekmart.co.za\/t-blog\/?p=6935"},"modified":"2021-05-28T11:34:33","modified_gmt":"2021-05-28T09:34:33","slug":"plc-flash-a-solid-state-candidate-for-analytics-and-archives","status":"publish","type":"post","link":"https:\/\/tekmart.co.za\/t-blog\/plc-flash-a-solid-state-candidate-for-analytics-and-archives\/","title":{"rendered":"PLC flash: A solid state candidate for analytics and archives?"},"content":{"rendered":"Reading Time-approximately:<\/span> 2<\/span> minutes<\/span><\/span>\n

We thought flash would end at QLC, but storage media makers are working on penta-level cell, which could push capacity to double figures, but at a further performance cost.<\/strong><\/h2>\n\n\n\n
\"Antony<\/figure>\n\n\n\n

By Antony Adshead<\/a><\/p>\n\n\n\n

When QLC\u00a0flash storage\u00a0drives arrived in the market last year, it looked like the storage media makers had pushed the manufacturing process\u00a0as far as it could go.<\/p>\n\n\n\n

But now,\u00a0Intel has signalled\u00a0that a further iteration of NAND solid state storage \u2013 PLC, or penta-level cell \u2013 may be on its way.<\/p>\n\n\n\n

That could mean flash drives that start to push towards 20TB, and while they will be cheaper to run than equivalent-sized spinning disk media, they will be limited in terms of\u00a0I\/O\u00a0performance, endurance and therefore use cases.<\/p>\n\n\n\n

Let\u2019s recap on what a move to PLC actually means.<\/strong><\/p><\/blockquote><\/figure>\n\n\n\n

Successive generations of flash drive have been developed by building on the number of states \u2013 of voltage switching between 0 and 1 \u2013 per flash cell.<\/p>\n\n\n\n

We started with the now-obsolete\u00a0single-level cell (SLC), with one 0 or 1 per cell, and added a further possible cell state to that with multi-level cell (MLC), which meant four possible switching outcomes (00, 10, 01, 11).<\/p>\n\n\n\n

Then triple-level cell (TLC) added another for seven possible voltage switches, then\u00a0quad-level cell (QLC)\u00a0provided 16 states and 15 possible switches. QLC drives are currently available up to about 8TB in capacity.<\/p>\n\n\n\n

Now PLC \u2013 if it can be productised \u2013 will almost double that and allow for 32 states and 31 switching outcomes.<\/p>\n\n\n\n

Each of these generations\u2019 increases in cell switching capability can be understood as adding to the capacity of drives in which they are used. So, for example, an\u00a0MLC drive\u00a0provides 4x that of an SLC drive, and so PLC drives will nearly double the capacity of QLC.<\/p>\n\n\n\n

But every increase in cell state capacity has come with a cost in terms of durability. As each generation has packed more electrical operations into a smaller space, the longevity of cells has been eroded.<\/p>\n\n\n\n

That is partly because, with multiple voltages necessary for multiple levels of switching, longer times are required to set and detect the charge. The other consequence of this is longer read and write times.<\/p>\n\n\n\n

Manufacturers will try to mitigate these issues\u00a0by over-provisioning capacity. Western Digital, for example, is working on \u201czoning\u201d, where data of certain types is restricted to certain areas on the flash die, with the aim of making data as near to write-once-read-many as possible.<\/p>\n\n\n\n

High-performance enterprise flash does not adhere to this principle, and flash drive maintenance sees data erased and moved as part of processes aimed at optimising performance.<\/p>\n\n\n\n

But the big question is: is PLC flash achievable as a product and what will its characteristics and limitations mean for possible use cases?<\/p>\n\n\n\n

Well, QLC is mainly aimed at use cases that see little change in data stored on devices that use it, and PLC will follow suit.<\/p>\n\n\n\n

That means lots of random I\/O and rapidly changing data are out. Instead, PLC, like QLC, will be best suited to reads, and preferably longer sequential reads.<\/p>\n\n\n\n

Micron QLC, for example, advertised 32x more I\/O than SATA spinning disk and 2x on throughput. We can expect those to be reduced for PLC.<\/p>\n\n\n\n

So, in terms of use cases, that could mean some machine learning workloads and archive usage.<\/p>\n","protected":false},"excerpt":{"rendered":"

Reading Time-approximately:<\/span> 2<\/span> minutes<\/span><\/span>We thought flash would end at QLC, but storage media makers are working on penta-level cell, which could push capacity to double figures, but at a further performance cost. By Antony Adshead When QLC\u00a0flash storage\u00a0drives arrived in the market last year, it looked like the storage media makers had pushed the manufacturing process\u00a0as far as it could go. But now,\u00a0Intel<\/p>\n

Read More<\/a><\/p>\n","protected":false},"author":114,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[134,38,35,8,4,30,31,3],"tags":[],"class_list":["post-6935","post","type-post","status-publish","format-standard","hentry","category-all-flash-arrays","category-best-practices-for-data-center-operations","category-data-center-facilities","category-data-center-hardware","category-datacenter-news","category-expert-advise-and-opinion","category-flash-memory","category-industry-news-and-expert-advise"],"_links":{"self":[{"href":"https:\/\/tekmart.co.za\/t-blog\/wp-json\/wp\/v2\/posts\/6935","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/tekmart.co.za\/t-blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/tekmart.co.za\/t-blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/tekmart.co.za\/t-blog\/wp-json\/wp\/v2\/users\/114"}],"replies":[{"embeddable":true,"href":"https:\/\/tekmart.co.za\/t-blog\/wp-json\/wp\/v2\/comments?post=6935"}],"version-history":[{"count":1,"href":"https:\/\/tekmart.co.za\/t-blog\/wp-json\/wp\/v2\/posts\/6935\/revisions"}],"predecessor-version":[{"id":6936,"href":"https:\/\/tekmart.co.za\/t-blog\/wp-json\/wp\/v2\/posts\/6935\/revisions\/6936"}],"wp:attachment":[{"href":"https:\/\/tekmart.co.za\/t-blog\/wp-json\/wp\/v2\/media?parent=6935"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/tekmart.co.za\/t-blog\/wp-json\/wp\/v2\/categories?post=6935"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/tekmart.co.za\/t-blog\/wp-json\/wp\/v2\/tags?post=6935"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}