Optane

New Book Explains Persistent Memory Programming

Cover picture of Intel's Persistent Memory bookAt January’s SNIA Persistent Memory Summit Intel was promoting a book titled: Programming Persistent Memory.  This book, aimed at programmers, explains how to develop applications programs that take advantage of persistent memory (PM) to avoid slower persists to SSDs, and also shows how to use Intel’s Optane DIMMs to increase a system’s main memory size.

On the software side the book explains how to design and optimize data structures for persistent memory, and it details persistent memory Application Program Interfaces (APIs) for C, C++, JavaScript, and other languages.  It also provides a trove of information on the open source Persistent Memory Development Kit (PMDK) libraries and tools.  The book shows numerous source code samples and examples that you can run on your own systems, and provides diagrams that help explain the various structures and processes embodied by the software.  It also explains how PM applications are Continue reading

Does Persistent Memory Improve Performance? Ask Oracle!

A model-by-model timeline of Oracle's Exadata product introductions with key specifications.At last month’s SNIA Persistent Memory Summit Oracle presenter Jia Shi, Sr. Director of Exadata Development, shared some statistics on the Exadata system’s history over the past ten years.  (Click on the graphic to the left to see the timeline.)  The speaker highlighted the fact that the system’s I/O performance has grown from 0.05 million IOPS ten years ago to 16 million IOPS today, a 320X improvement!  Shi said that Exadata was designed to be “the ideal database hardware with smart system software and automated management.”  There’s every reason for her to be proud of her own work with this product!

The most recent iteration of the system, X8M, released last September, takes advantage of Persistent Memory (PM) in the  form of Intel’s new Optane DIMMs (formally called “The Intel Optane DC Persistent Memory module”).  The presenter said she was diligently working on this new approach at this time last year – so diligently, in fact, that she was unable to attend the 2019 Persistent Memory Summit even though she was working on a pioneering implementation of PM technology!

While the timeline in this post’s graphic doesn’t Continue reading

SNIA Webcast: Emerging Memories

This shows the cover slide for the SNIA webcast presentation titled "What a Year it Was and Where We Need To Go in Emerging Memory"On Tuesday, January 14, Tom Coughlin and I were featured in a BrightTalk webinar hosted by the Storage Networking Industry Association (SNIA).  A recording of this webinar has been posted so that you can view it at your convenience.

This webinar looks at emerging memories and where they now stand, giving a glance at the ground that has yet to be covered before these new memories gain widespread acceptance as persistent memory in general-purpose computing.

The content of the presentation is excerpted from a 172-page report jointly published by Objective Analysis and Coughlin Associates that covers the gamut of emerging memory technologies, the companies involved (49 of them!), and predicts how the market for these new memories should develop with forecasts for the memories, as well as for the equipment used to manufacture them.  This is the 2019 update of a very well-received report originally published in 2017.

The webinar is a little less than an hour long, and about half of it consists of audience questions which we address in the second half.

You can view and listen to it by clicking HERE.

And, if you’re interested in the report, you can purchase a copy for immediate download from the Objective Analysis website by clicking HERE.

 

Micron’s New XPoint SSD Finally Arrives

Micron X100 3D XPoint SSDAt its October Insight Conference Micron Technology finally revealed its 3D XPoint SSD, dubbed the X100.

While the company didn’t disclose too much about the device, it did brag about its speed, claiming that the X100 is the world’s fastest SSD, running three times faster than the fastest NAND flash SSDs and almost three times the speed of other XPoint SSDs.  The product is said to provide a very impressive 2.5 million IOPS for 4kB random reads at a queue depth of 1 and to support a 9GB/second bandwidth in read, write, and mixed traffic.  (NAND flash SSDs perform much better at reads than at writes due to the underlying NAND chips’ extraordinarily lopsided read and write specifications, among other quirks.)

Just as Intel has done, Micron plans to introduce storage products first, before bringing out a memory module to fit into a DIMM slot.

How did Micron achieve this impressive level of performance?  Well, in addition to Continue reading

Intel’s Optane: Two Confusing Modes. Part 4) Comparing the Modes

Exploding HeadThis post completes The SSD Guy’s four-part series to help explain Intel’s two recently-announced modes of accessing its Optane DIMM, formally known as the “Intel Optane DC Persistent Memory.”

Comparing the Modes

In the second and third parts of this series we discussed Intel’s Memory Mode and the company’s App Direct Mode.  This final part aims to compare the two: When would you use one and when the other?

There’s really no simple answer.  As with all benchmarks, certain applications will perform better with one mode than with another, while other applications will behave the opposite way.  Adding to the problem is the fact that App Direct Mode actually supports not one but four different access methods, which will be further explained below.  As a rule of thumb performance for large serial accesses might be Continue reading

Intel’s Optane: Two Confusing Modes. Part 3) App Direct Mode

Exploding HeadThis post is a continuation of a four part series in The SSD Guy blog to help explain Intel’s two recently-announced modes of accessing its Optane DIMM, formally known as the “Intel Optane DC Persistent Memory.”

App Direct Mode

Intel’s App Direct Mode is the more interesting of the two Optane operating modes since it supports in-memory persistence, which opens up a new and different approach to improve the performance of tomorrow’s standard software. While today’s software operates under the assumption that data can only be persistent if it is written to slow storage (SSDs, HDDs, the cloud, etc.) Optane under App Direct Mode allows data to persist at memory speeds, as also do other nonvolatile memories like NVDIMMs under the SNIA NVM Programming Model.

App Direct Mode implements the full SNIA NVM Programming Model described in an earlier SSD Guy post and allows software to Continue reading

Intel’s Optane: Two Confusing Modes. Part 2) Memory Mode

Exploding HeadThis post is the second part of a four part series in The SSD Guy blog to help explain Intel’s two recently-announced modes of accessing its Optane DIMM, formally known as the “Intel Optane DC Persistent Memory.”

Memory Mode

The most difficult thing to understand about the Intel Optane DC Persistent Memory when used in Memory Mode is that it is not persistent.  Go back and read that again, because it didn’t make any sense the first time you read it.  It didn’t make any sense the second time either, did it?

Don’t worry.  This is not really important.  The difficulty stems from Intel’s marketing decision to call Optane DIMMs by the name “Intel Optane DC Persistent Memory.”  Had they simply called them “Optane DIMMs” like everyone expected them to then there would have been Continue reading

Intel’s Optane: Two Confusing Modes. Part 1) Overview

Exploding HeadIntel recently announced two operating modes for the company’s new Optane DIMMs, formally known as “Intel Optane DC Persistent Memory.”  The company has been trying to help the world to understand these two new operating modes but they are still pretty baffling to most of the people The SSD Guy speaks to.  Some say that the concepts make their heads want to explode!

How does Optane’s “Memory Mode” work?  How does “App Direct” Mode work?  In this four-part series will try to provide some answers.

Like all of my NVDIMM-related posts, this series challenges me with the question: “Should it be published in The SSD Guy, or in The Memory Guy?”  This is a point of endless confusion for me, since NVDIMM and Intel’s Optane blur the lines between Memory and Storage.  I have elected to post this in The SSD Guy with the hope that it will be found by readers who want to understand Optane for its storage capabilities.

Memory Mode is the easy sell for the short term.  It works with all current application software without modification.  It just makes it look like you have a TON of DRAM.

App Direct Mode is really cool if Continue reading

What is SNIA’s Persistent Memory Programming Model?

SNIA Persitent Memory Summit LogoIn this post The SSD Guy will discuss the SNIA Nonvolatile Memory (NVM) Programming Model, a framework to allow standard applications to take advantage of nonvolatile, or persistent, memory in any system that includes persistent memory,

This model is enormously important to the future of computing, yet few people even know that it exists.  It’s a fundamental change to the way that application programs access storage that will have significant ramifications to computer architecture and performance over the long term.

Here’s why: The industry is moving towards larger-scale systems that mix persistent memory with standard DRAM into a single memory address space.  Persistent memory has an advantage over volatile DRAM, since it maintains data after power is removed or lost.  Because of this certain application programs will want to know which memory is volatile and which is persistent and to take advantage of whatever persistent memory the system might provide.  I say “Larger-Scale” systems because small systems often combine Continue reading

An NVDIMM Primer (Part 2 of 2)

AgigA RamCardTwoThis post is the second of a two-part SSD Guy series outlining the nonvolatile DIMM or NVDIMM.  The first part explained what an NVDIMM is and how they are named.  This second part describes the software used to support NVDIMMs (BIOS, operating system, and processor instructions) and discusses issues of security.

Software Changes

Today’s standard software boots a computer under the assumption that the memory at boot-up contains random bits — this needed to be changed to support NVDIMMs.  The most fundamental of these changes was to the BIOS (Basic I/O Subsystem), the code that “wakes up” the computer.

The BIOS is responsible for detecting all of the computer’s hardware and installing the appropriate drivers, after which it loads the bootstrap program from the mass storage device into the DRAM main memory.  When an NVDIMM is used the BIOS must Continue reading