September 2012 – The SSD Guy Blog

How Controllers Maximize SSD Life – External Data Buffering

Since NAND flash is weakened by erase/write cycles then it would make sense to try to reduce those cycles to prolong the life of an SSD right? That’s what external data buffers are designed to do.

There are many ways to use RAM (either a RAM internal to the SSD controller chip or a discrete DRAM chip on the SSD’s printed circuit card) to stage data in a way that will reduce erase/write cycles.

One is to perform a function called “Write Coalescing.” This involves Continue reading “How Controllers Maximize SSD Life – External Data Buffering”

Samsung Introduces TLC SSD

Samsung on Monday introduced a new “840” SSD series which reviewers have found is based on TLC flash.

Oddly enough the press release for this product seems only to have been distributed in Korea to reviewers who attended a special introduction of the device. The SSD Guy has not been given the specifications presented at the event, and had to ask Samsung for a copy of the press release.

The press release focuses on the product’s 100,000 read IOPS, that it comes in two versions, the “Pro” model for the enterprise and another model for client applications, and the fact that the controller uses a new design based on three ARM cores. A read IOPS figure of 100,000 is very high performance for a SATA drive! One has to wonder if the client market will be able to distinguish between this level of performance and drives with fewer than 10,000 IOPS.

Other specifications Continue reading “Samsung Introduces TLC SSD”

Toshiba Announces its Hybrid Drive

Now that we have seen announcements of hybrid drives from Western Digital and Seagate, Toshiba arrives with a formal announcement of the product that was on display at last month’s Flash Memory Summit. Two 2.5″ Toshiba hybrid drives are starting to sample at 750GB and 1TB capacities. Both have 8GB NAND caches, 6Gb/s SATA 3 interfaces, and 5,400RPM spindle speeds. They are both built using 32nm SLC NAND, Toshiba’s “generation before last” technology, preceding the 24nm and 19nm nodes shipping in high volume today.

More importantly, both are 9.5mm in height, a thickness that renders them difficult to incorporate into the 18mm maximum thickness of the smaller Ultrabooks – a notebook form factor that Intel is heavily promoting.

How is this whole market Continue reading “Toshiba Announces its Hybrid Drive”

Storage Developer Conference Focuses on SSDs

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 “Storage Developer Conference Focuses on SSDs”

How Controllers Maximize SSD Life – Better Wear Leveling

In this post we will explore how the right wear leveling algorithm can help a controller maximize the life of an SSD.

Wear leveling is a fact of life with NAND flash – blocks start to suffer bit failures after a certain number of erase/write cycles (usually specified from the thousands to the hundreds of thousands) and it is only natural that software will attempt to over-write some blocks more than others. In order to prevent this from causing failures, all of today’s SSD, USB flash drive, and flash card controllers incorporate some sort of wear leveling.

This is a simple re-mapping of the contents of the flash chips. A more graphical explanation is Continue reading “How Controllers Maximize SSD Life – Better Wear Leveling”

The Week of CEO Changes

This week has gotten off to an odd start. On Monday OCZ CEO Ryan Peterson resigned, after having built the company from a supplier of PC cases, power supplies and DRAM for gamers into a leading SSD maker, and then launching a successful IPO. On Tuesday STEC’s CEO Manouch Moshayedi announced (via an SEC filing) that he will step down “pending resolution of a civil complaint filed against him by the Securities and Exchange Commission.” Finally today Virident announced the hiring of Mike Gustafson of BlueArc repute to become CEO while former CEO and co-founder Kumar Ganapathy shifts his focus to business strategy, new product development and strategic partnerships.

What will Thursday and Friday bring? Continue reading “The Week of CEO Changes”

How Controllers Maximize SSD Life

How do controllers maximize the life of an SSD? After all, MLC flash has a lifetime of only 10,000 erase/write cycles or fewer and that is a very small number compared to the write traffic an SSD is expected to see in a high-workload environment, especially in the enterprise. Still, MLC is becoming the norm in the enterprise.

How do they do that?

This is where SSD architects really earn their pay. There are eight basic techniques that The SSD Guy knows of to extend SSD life beyond Continue reading “How Controllers Maximize SSD Life”

Seagate Updates Hybrid Drive

At the Intel Developer Forum Intel showed Seagate‘s updated Momentus XT Hybrid Solid State Drive in operation. The new drive is only 7mm thick, significantly thinner than the 9.5mm Momentus XT that the company has been shipping for the past 2 years.

This is significant because the 13mm target thickness of the Ultrabook platform is extremely difficult to achieve using a 9.5mm drive, yet the performance specification of the Ultrabook requires the use of NAND flash, either in the form of a full-blown SSD, an HDD with an additional cache SSD, or a hybrid drive. Of the three choices, Continue reading “Seagate Updates Hybrid Drive”

WD Introduces Hybrid HDD

Western Digital Corporation on Monday announced that it is sampling its long-awaited hybrid HDD. WD claims that the 500GB 2.5″ device is the thinnest in the industry at 5mm. So far Seagate has been alone in this field with its Momentus XT Solid State Hybrid Drive. There are some significant differences between the two drives:

Seagate uses SLC flash while WD uses MLC. There is more than a 10:1 price premium for SLC flash
Seagate’s hybrid ships in 750GB and 500GB capacities while WD’s is 500GB
Seagate’s device is 9.5mm thick, while WD’s is 5mm

The last point is extremely Continue reading “WD Introduces Hybrid HDD”

IOPS Survey – Still Seeking Participants

Tom Coughlin and I are still seeking IT professional inputs for our 5-minute IOPS survey.

Please take a brief moment to share your thoughts on the importance of I/O in your system. It’s only 5 multiple-choice questions.

Click HERE and let us know what kind of storage performance you need. Even a hunch is good.

Many thanks!