NVMe-oC: Wolley’s New Take on CXL-Based SSDs

Vertical block diagram with a CPU at the top, a CXL link below, and a dashed-line box below that. The Dashed box contains two side-by-side devices: NVMe NAND and Memory. Two bidirectional arrows communicate from these two devices through the CXL link to the CPU. A little red arrow shows data moving directly from the NAND into the memory while bypassing CXL.With all the recent interest in CXL, and its ability to connect a processor to any memory, no matter the speed, it’s only natural that someone would try using it for SSDs.  This notion is the basis for the Memory-Semantic SSD, or MS-SSD.

But MS-SSDs suffer from the same problem as SSDs, hard drives, and other mass storage.  The basic concept requires Continue reading “NVMe-oC: Wolley’s New Take on CXL-Based SSDs”

WDC’s Top-to-Bottom Storage Fabric Approach

Small cropped version of the chassis photo further down in the blog.Western Digital launched a storage fabric architecture in August that aims to address certain issues that occur with existing storage systems.  WDC is furthermore taking a number of steps to try to promote this architecture’s adoption into mainstream storage.  It’s an interesting approach that The SSD Guy thought was worth discussion.

The company is working to address the problem of Continue reading “WDC’s Top-to-Bottom Storage Fabric Approach”

High Availability in an m.2 Format

Photo of finger pusing on hinge in center of m.2 HA SSDThe m.2 SSD format has become wildly successful in the data center for use as a boot drive and even in SSD arrays.  The m.2 format supports either the SATA or the NVMe interface,  Something that has been missing, however, is a version of this format for high-availability (HA) systems.  These are mission-critical systems that cannot fail, no matter what.

Until today HA systems had to Continue reading “High Availability in an m.2 Format”

Podcast: Flash Memory Summit 2019

GreybeardsThose of you who enjoy listening to podcasts may want to hear Ray Lucchesi (Silverton Consulting) and Keith Townsend (The CTO Advisor) interview The SSD Guy for their series “Greybeards on Storage.”

This interview is the series’ 86th episode covering the world of storage.  These guys do a fantastic job of probing this industry with great enthusiasm and insight.

This episode is a 40-minute compendium of the sights and goings-on at the August 2019 Flash Memory Summit along with observations on the industry in general.  It’s not strictly structured, and not strictly serious, but just three industry insiders having a lot of fun sharing their observations.

Some of the broad range of subjects that Continue reading “Podcast: Flash Memory Summit 2019”

IBM Aligns Itself with High Speed NVMe-based Storage

NVMe LogoIBM has announced that it is developing Non-Volatile Memory Express (NVMe) solutions to provide significantly lower latency storage.

NVMe is an interface protocol designed to replace the established SAS and SATA interfaces that are currently used for hard drives and SSDs. Coupled with the PCIe hardware backplane, NVMe uses parallelism and high queue depths to significantly reduce delays caused by data bottlenecks and move higher volumes of data within existing flash storage systems.

IBM has set itself to the task of optimizing the entire storage hierarchy, from the applications software to flash storage hardware, and is re-tooling the end-to-end storage stack to support NVMe. The company recognized years ago that both hardware and software would need to be redesigned to satisfy the needs of ultra-low latency data processing.

The company last year released products with Continue reading “IBM Aligns Itself with High Speed NVMe-based Storage”

NGD’s 24TB SSD Is Just The First Step

NGD LogoWith the tagline: “Bringing intelligence to storage” start-up NGD Systems, formerly known as NexGen Data, has announced a 24 terabyte SSD that the company claims to be the highest-capacity PCIe/NVMe device available.

The read-optimized Catalina SSD employs a lot of proprietary NGD technology: Variable rate LDPC error correction, unique DSP (digital signal processing) algorithms, and an “Elastic” flash transition layer (FTL), all embodied in an NGD-proprietary controller.  This proprietary technology allows Catalina to offer enterprise performance and reliability while using TLC flash and less DRAM than other designs.

NGD claims that the product is already shipping and is being qualified by major OEMs.

Based on some of the company’s presentations at past years’ Flash Memory Summits the controller has been carefully balanced to optimize cost, throughput, and heat.  This last is a bigger problem than most folks would imagine.  At the 2013 Hot Chips conference a former Violin Memory engineering manager told the audience Continue reading “NGD’s 24TB SSD Is Just The First Step”

OCZ Comes Roaring Back with NVMe SSD Debut

The OCZ Z-Drive 6000It’s really something to see a company recover from a big challenge, and signs of that happened this week with OCZ’s introduction of a new NVMe-based PCIe SSD they call the Z-Drive 6000 series.

This replacement for the company’s Z-Drive 4000 series is a complete redesign with an obsession for performance.  OCZ tells me that they moved from a 2-hop design to a 1-hop by using the PMC Princeton PCIe SSD controller, and have passed the University of New Hampshire Interoperability Labs’ compliance tests to NVMe 1.1B compliance.

But how does it perform?  Well the 1-hop design helps reduce latency (which is just starting to overshadow IOPS in users’ minds) and the latency of this SSD is significantly lower than competing NVMe SSDs: between 25-30μs, figures that OCZ tells me are very consistent, a big plus for enterprise applications.  As for IOPS, the device can perform under a 70/30 Read/Write load at 330K.

The 6000 series is provided in both standard MLC and eMLC for those who want the security of eMLC and are willing to sacrifice a little performance to sleep better at night.

This product is a good fit for the market needs, and shows how devoted OCZ and its parent Toshiba are to providing high performance in the SSD marketplace.

 

Where does NVRAM Fit?

AGIGARAM DDR4 NVDIMM (Photo Courtesy of AgigA Tech)There’s been a lot of interest in NVRAM recently.  This technology has been lurking in the background for decades, and suddenly has become very popular.

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 “Where does NVRAM Fit?”

LSI SandForce SSD Controllers Move the Knee in the Curve

LSI SandForce SF3700 Controller DuraWrite ImprovementsLSI’s SandForce has just rolled out its SF3700 family of four SSD controllers aimed at the Entry Client, Mainstream Client, Value Enterprise, and Enterprise Storage marketplaces. Performance is impressive, with worst-case random PCIe IOPS at 150K read/81K write and 94K/46K for the SATA interface.

The SF3700 family builds on the division’s first two product families by adding a choice of PCIe or SATA interfaces, LDPC error correction, and a boosted set of flash management features.  The SSD Guy will explore this last point after highlighting the other two.

By providing both PCIe and SATA interfaces LSI is directly addressing the future: PCs are aiming to move to the m.2 SSD specification rather than Continue reading “LSI SandForce SSD Controllers Move the Knee in the Curve”

One-Hop vs. Two-Hop PCIe SSDs

Bunny HopLately a number of PCIe offerings have hit the SSD market.  The SSD Guy breaks them into two camps: One-Hop SSDs, in which the commands are translated directly from PCIe to the NAND flash without going through an intermediary protocol, and Two-Hop SSDs, which use off-the-shelf HBAs and SATA SSD controllers to move commands first from PCIe to SATA then from SATA to NAND.  There are aslo versions that go through SAS: PCIe to SAS, then SAS to NAND.

The SSD Guy figured that Easter would be a good time to talk about these since everyone already has the Easter Bunny hopping through their minds!

It’s not hard to understand why Continue reading “One-Hop vs. Two-Hop PCIe SSDs”