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
Last week the Storage Networking Industry Association (SNIA) hosted its 2012 Storage Developer Conference (SDC). There was a strong focus on SSDs at this forum, with 15 papers, one keynote, and a panel devoted to the subject.
Consider that the 2008 SDC was the first such conference in which SSDs were discussed. This year I commented to another participant: “Some day we will look back on this transition and be amazed at how suddenly SSDs became fundamental to the way storage is configured!”
Many of those papers and keynotes made it clear that the PCI Express (PCIe) interface has Continue reading
Calypso Systems ran the SNIA SSD Performance Test Specification (PTS), outlined in an earlier post in this blog, on seventeen SSDs and a single HDD. The results appear, in miniature, in the graphic for this post. Continue reading