From time to time IT managers ask The SSD Guy if there’s an easy way to compare SSDs made with MLC flash against those made using eMLC flash. Most folks understand that eMLC flash is a less costly alternative to SLC flash, both of which provide longer wear than standard MLC flash, but not everyone realizes that eMLC’s superior endurance comes at the cost of slower write speed. By writing to the flash more gently the technology can be made to last considerably longer.
So how do you compare the two? OCZ introduced MLC and eMLC versions of the same SSD this week, and this provides a beautiful opportunity to explore the difference.
As you would expect, the read parameters are all identical. This stands to reason, since Continue reading
I have to admit that it’s embarrassing when The SSD Guy misses something important in the world of flash storage, but I only recently learned of a paper that Baidu, China’s leading search engine, presented at the ASPLOS conference a year ago. The paper details how Baidu changed the way they use flash to gain significant benefits over their original SSD-based systems.
After having deployed 300,000 standard SSDs over the preceding seven years, Baidu engineers looked for ways to achieve higher performance and more efficient use of the flash they were buying. Their approach was to strip the SSD of all functions that could be better performed by the host server, and to reconfigure the application software and operating system to make the best of flash’s idiosyncrasies.
You can only do this if you have control of both the system hardware and software.
The result was SDF, or “Software-Defined Flash”, a card that Continue reading
Erik Logan of Pogo Linux sent me a link to an amusing & informative video he and his company put together called A Brief History of SSDs. In the video Erik (pictured) tells of Pogo Linux’ experience with SSDs.
The company has a lot of hands-on SSD experience: Pogo Linux ships servers and storage and has ramped SSD shipments (as a percent of all drives) from single digits three years ago to the point where SSDs now account for 31% of all drives they ship. Erik shared with me that: “Sorting through the Continue reading
Tom Coughlin and I have just released a new report that helps shed a lot of light on a pretty challenging subject: We asked nearly 200 IT managers to tell us how much storage performance their systems require. They provided candid replies about their IOPS, latency, and capacity needs for a number of leading applications.
SSD spec sheets, might lead you to believe that power is just not an issue. For example, Samsung lists the power use for a 512GB 830 SSD at 0.127W (typical) for “Active Power Use”. This implies very low demands on the system power supply.
If you do some more research, you find that the peak power usage is a lot higher. AnandTech, in a review article reports sequential write power draw at 5.14W and random write power draw at 5.8W. In that 2.5” SSDs use the 5V power rail exclusively, this is more than Continue reading
In his Flash Memory Summit keynote on Wednesday, Micron VP and Chief Memory Systems Architect Ed Doller made a compelling demonstration of the power and performance advantages of a new approach to computing.
With true showmanship, Doller had his co-workers hand out buttons with LED lights to the entire audience. The LEDs in these buttons were either green or blue, with the colors randomly dispersed among the crowd. Doller asked the entire audience to turn on their lights, then called one row of the audience to file up to the stage so he could determine whether each person’s button was blue or green.
He pointed out that this was like having a single CPU check the contents of a drive. He then asked why things should work this way – wouldn’t it be more sensible to Continue reading
I had the opportunity to participate in a round table webinar covering the best practices for solid state storage on July 18. The hour-long session (including Q&A) can be replayed at BrightTalk.
In this round table webinar entitled Best Practices for Solid State Storage Implementation storage analyst Tom Coughlin moderated three of us, Radoslav Danilak of Skyera, Esther Spanjer of SMART Storage Solutions, and The SSD Guy (Yours Truly) in a 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.
How sensitive are they? Well, I have seen some overblown claims from SSD makers that shock will cause HDD head crashes. I am not sure that I believe such claims, but I certainly do believe that an HDD’s actuator (the read/write head mechanism) can be shaken away from its track, causing a Continue reading