Sometimes it’s enlightening to compare several viewpoints on similar data. At yesterday’s SNIA Persistent Memory Summit a number of presentations provided interesting overlapping views on certain subjects.
One of particular interest to The SSD Guy was latency vs. IOPS. Tom Coughlin of Coughlin Associates and I presented the findings from our recently-published IOPS survey report and in Slide 19 displayed the basic chart behind this post’s graphic (click to enlarge, or, better yet, right-click to open in a new tab). This chart compares how many IOPS our respondents said they need for the storage in their most important application, and compared that to the latency they required from this storage. For comparison’s sake we added a reference column on the left to roughly illustrate the latency of various standard forms of storage and memory.
You can see that we received a great variety of inputs spanning a very wide range of IOPS and latency needs, and that these didn’t all line up neatly as we would have anticipated. One failing of this chart format is that it doesn’t account for multiple replies for the same IOPS/latency combination: If we had been able to include that the chart would have shown a clearer trendline running from the top left to the lower right. Instead we have a band that broadly follows that trend of upper-left to lower-right.
Two other speakers presented the IOPS and latency that could be Continue reading
This Sunday (Sept. 20, 2015) I will be presenting my company’s findings on the 3D XPoint memory that was introduced by Intel and Micron in July. I will be speaking at the Storage Networking Industry Association (SNIA) Storage Developer Conference (SDC) Pre-Conference Primer. You can click the name to be taken to the agenda.
This won’t be the only talk about persistent memory technology at the conference. Prior to my presentation storage consultants Tom Coughlin and Ed Grochowski will give an overview of advances in nonvolatile memories, and following my presentation will be two Intel talks.
Intel will be covering this new technology a lot during the conference. Of a total of 120 presentations at the conference and pre-conference primer, Intel will be presenting nine, seven of which directly name persistent memory or nonvolatile memory in the title. Other firms will also be talking about NVM: AgigA, Calypso, HP, Pure Storage, and SMART Modular. Even Microsoft alludes to it in a couple of its presentation titles. Persistent memory is a hot issue.
So, the question for readers of The SSD Guy blog is: “Will this do away with SSDs?”
This is a question that was Continue reading
What is NVRAM? Quite simply, it’s DRAM or SRAM that has a back-up flash memory a small controller, and a battery or super-capacitor. During operation the DRAM or SRAM is used in a system the same way that any DRAM or SRAM would be used. When power is interrupted the controller moves all of the data from the DRAM or SRAM to the flash using the backup power from the battery or super-capacitor. When power is restored, the controller moves the contents of the flash back into the SRAM or DRAM and the processor can resume operation where it left off.
In some ways it’s storage and in some ways it’s memory, so Continue reading
We have just finished up a webcast (now available for replay) that gives a preview of five of the solid state storage presentations that will be given at the upcoming Storage Plumbing and Data Engineering Conference – SPDEcon for short – hosted by the Storage Networking Industry Association (SNIA) on June 10-12 at the Hyatt Regency hotel in Santa Clara, California.
The report is based upon a survey that asked IT managers about their enterprise IOPS requirements. The webinar gives a taste of the report’s contents, and explains the survey methodology. During the course of the webinar and at the end Tom and I answered a number of listener questions relating to the content.
The presentation also includes a little plug for SNIA’s client IOPS survey which is being run by downloading a program called the Workload I/O Capture Program, or “WIOCP.”
A replay of this webinar is available on the BrightTalk website.
The presentation was well received by our audience. Have a listen.
Jim Pappas of Intel, a fellow member of SNIA (the Storage Networking Industry Association) shared a really intuitive way to understand storage delays at the last Storage Developer Conference (SDC). It’s very simple. First consider these two facts:
- The difference between the speed of system memory and that of a hard disk drive (HDD) is roughly 6 orders of magnitude, or 1 million times
- SSDs split the gap. An SSD is about 1,000 times faster than an HDD, and is about 1,000 times slower than system memory. Memory access times are measured in nanoseconds (ns), SSDs in microseconds (µs) and HDDs in milliseconds (ms)
The problem with understanding this (ns, µs, ms) is that Continue reading
TCO has been used as an argument for buying anything from compact fluorescent bulbs to Jaguar automobiles.
The argument usually revolves around an item whose initial price is higher, but which has lower ongoing (or operating) costs, and when these costs are combined, the higher-priced item proves to cost less to own over the long run. In the case of a compact fluorescent (CF) bulb, the bulb may cost $7, versus $1 for an incandescent bulb, but it consumes 18 Watts compared to the 75 Watts consumed by the incandescent bulb it replaces. In addition the CF bulb lasts ten times as long (10,000 hours vs. 1,000 hours.) This works out to a savings of 470 kWh – or about $50 – plus $3 in bulb costs. Continue reading
SNIA (The Storage Networking Industry Association) has conferred a great honor upon the SSD Guy by bringing all of the blog posts in the series How Controllers Maximize SSD Life into a single printed volume of the same name.
Readers can either ask for a print copy from SNIA, or can download a pdf rendition by visiting the SNIA SSSI (Solid State Storage Initiative) education web page.
Few Sysadmins really understand what’s happening in the storage interface of their systems, yet there’s a lot of talk about SSDs with wide-ranging IOPS figures along with case studies of how these have helped solve system slowdowns. The big question is: “How do you determine what your storage bottleneck is, and even whether or not one exists at all?”
Tom Coughlin and I discovered a very low level of understanding of this issue when we performed the IOPS survey late last year that we documented in our report: How Many IOPS do You Really Need? A disconcerting number of respondents gave replies that Continue reading