NVMe-oC: Wolley’s New Take on CXL-Based SSDs

Vertical block diagram with a CPU at the top, a CXL link below, and a dashed-line box below that. The Dashed box contains two side-by-side devices: NVMe NAND and Memory. Two bidirectional arrows communicate from these two devices through the CXL link to the CPU. A little red arrow shows data moving directly from the NAND into the memory while bypassing CXL.With all the recent interest in CXL, and its ability to connect a processor to any memory, no matter the speed, it’s only natural that someone would try using it for SSDs.  This notion is the basis for the Memory-Semantic SSD, or MS-SSD.

But MS-SSDs suffer from the same problem as SSDs, hard drives, and other mass storage.  The basic concept requires Continue reading “NVMe-oC: Wolley’s New Take on CXL-Based SSDs”

Flexible Data Placement Means Better SSDs

Overlay with Fadu's logo over Meta's logoOne of the most compelling keynotes at the Flash Memory Summit last August was presented by SSD controller maker FADU Technology and social media giant Meta (Facebook).  These two companies were advocating a new way of managing SSDs called: “Flexible Data Placement.”  The SSD Guy believes that these two companies’ findings are pretty remarkable and well worth sharing.

Ross Stenfort from Meta presented a timeline showing that since 2019 Meta and Microsoft (Azure) have been working Continue reading “Flexible Data Placement Means Better SSDs”

What is Write Amplification?

A 4x4 checkerboard of red, green, and white squaresFor a long time, The SSD Guy has been talking about Write Amplification without explaining what It is.  This post is intended to fix that.

Write amplification is an internal issue for NAND flash SSDs that arises from the way that NAND chips work.  It doesn’t exist in standard HDDs, nor did it exist in DRAM SSDs before we had NAND ones.  In a nutshell it’s the Continue reading “What is Write Amplification?”

Mardi Gras vs. SSD Garbage Collection

Silhouette of a hopping rabbitMardi Gras is a good time for The SSD Guy to bend your mind.  It’s the day before Ash Wednesday kicks off Lent, the penitential season leading up to Easter.

And it never seems to happen on the same date.

I will compare SSD garbage collection to the timing of the Lenten season and Easter.  There are surprising similarities.

Very few people understand Continue reading “Mardi Gras vs. SSD Garbage Collection”

Smarter NAND for Better SSDs

NAND part of one of the diagrams below.Micron presented something really interesting during the company’s Investor Day Conference last week, but it didn’t seem to get any press coverage.  The company naturally repeated its plan to become a more important supplier of data center SSDs, but what The SSD Guy was most interested in were a few comments they gave for choosing to make vertically-integrated SSDs.  Micron now makes not only the NAND and the DRAM internal to its SSDs, but also the controller.

Why would a company Continue reading “Smarter NAND for Better SSDs”

An SSD You Can’t Wear Out

Infinity symbol overlaid on a Nimbus ExaDrive DC SSD photoThere’s something really odd about Nimbus Data’s colossal 100 terabyte ExaDrive DC SSDs, and it’s not their sheer capacity (although that’s pretty remarkable by itself!)  The strange thing is that they can’t be worn out.  It’s physically impossible.

At first glance that may seem wrong-headed.  NAND flash wears out, and that was the cause of a lot of Continue reading “An SSD You Can’t Wear Out”

Whatever Happened to “Hero” SSDs?

Bodybuilder with the insides of an SSD superimposedIt seems not so long ago that there were frequent press releases, and showings at trade shows, of “Hero” SSDs.  These demonstration models (which weren’t always released as products) always had some unique and impressive attribute.  They may have had a higher capacity than any SSD known to humankind, or perhaps they had phenomenal endurance.  Some broke the IOPS barrier.

The SSD Guy doesn’t remember anyone Continue reading “Whatever Happened to “Hero” SSDs?”

Using 176-Layer NAND for High-Capacity Data Center SSDs

Chart with a line that goes pretty flat from 1.5 to 2ms latency 0 to 350K IOPSMicron recently briefed The SSD Guy on its new 7450 SSD series, a range of high-capacity data center SSDs offered in an impressive number of capacities and form factors spanning M.2, U.3 and E1.S. The 7450 is a mainstream drive targeted at a wide variety of data center applications, including common, mixed, and random workloads.

The 7450 series is an evolution of Micron’s 7400 series which was first introduced at 96 layers and was based on Continue reading “Using 176-Layer NAND for High-Capacity Data Center SSDs”

Using AI to Manage Internal SSD Parameters

Old wise man with a disk symbol coming out of his headFor a long time The SSD Guy has meant to write something about the budding use of AI in SSDs.  It’s an interesting approach whose time has come.

If you’re not conversant with AI, and maybe find the whole subject to be daunting, don’t worry.  AI comes in many forms, and some are very simple.  When major Internet firms like Google and Facebook use AI to Continue reading “Using AI to Manage Internal SSD Parameters”

Computational Storage Hits the Mainstream

Chart showing two lines on a graph of performance vs number of SSDs. With "Scale In" the performance is proportional to the number of SSDs. With a standard server the performance diesn't change. With 16 SSDs the performance is 4 timeas as much, and with 32 SSDs it's 8 times as much.There’s an idea that has been kicking around for a number of years, and it seems now to be gaining traction.  The idea is to use the inherent smarts and high available bandwidth within an SSD to perform functions that would normally be done by a server’s processor thereby reducing the load on the processor while minimizing the amount of data that needed to make a round trip from the SSD to the processor and back for some trivial function.

Such data movement is said to consume a very Continue reading “Computational Storage Hits the Mainstream”