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Computer Weekly’s 2015 review of PCIe SSD products focused on consolidation in the market. At the time, a range of acquisitions had taken place and some suppliers left the market altogether.
In 2016, we see a divide between suppliers that continually evolve their server flash products and those that appear to have stalled in provision of updates to their offerings.
HGST, SanDisk and Micron appear to have slowed their product releases and instead focused on other product ranges – such as traditional flash drives – or on developing base technology for their products, which is the case for Micron with 3D Nand and 3D XPoint on the horizon.
The other suppliers in our survey have pushed on with products that deliver increased capacity and performance. Only Samsung appears to have evolved to use new technology, with the PM1725 and PM953 based on 3D TLC Nand.
NVMe support isn’t consistent. Typically, only suppliers releasing products have moved to support the NVMe standard. There do, however, seem to be more products available using the M.2 format, including Sandisk’s X400 M.2 2280 at only 1.5mm thick.
The PCIe SSD market doesn’t seem to have evolved as fast as the traditional drive-format market. This is presumably because PCIe SSD hardware had a significant price mark-up over their SAS/Sata-format counterparts. Therefore, customers are more likely to push these products until the end of their useful lifetime.
The more widespread adoption of TLC flash may see this change, as it offers suppliers the ability to deliver products to a lower price/capacity point. This refresh may coincide with more suppliers releasing NVMe supported products, as they play catch-up with leaders such as Intel and Samsung.
HGST offers two PCIe SSD product lines: The Ultrastar brand and FlashMAX.
At the time of the 2015 review, HGST had started shipping the Ultrastar drives, based on MLC Nand technology and PCIe 3.0 x4. The SN150 and SN100 models have not been refreshed since last review and continue to offer 3GBps (read) and 3GBps (write) capability, with up to 743,000 4K read input/output operations per second [IOPS] and 140,000 4K IOPS (write).
The FlashMAX III and II products use PCIe 2.0 x8 with MLC Nand technology, in capacities of 2.2TB, 1.1TB (FlashMAX III) and 4.8TB (FlashMAX II).
FlashMAX III performance is rated at 531,000 4K IOPS (read) and 59,000 4K IOPS (write), while the figures for FlashMAX II are 269,000 IOPS and 51,000 IOPS respectively.
HGST released the Ultrastar SN100 and SN150 in 2015, both of which are NVMe-compliant.
Intel continues to extend the range and breadth of its PCIe SSD offerings.
In addition to the existing P3700, P3600 and P3500 products, the company introduced the DC P3608 Series in September 2015. These new devices are available in 1.6TB, 3.2TB and 4TB capacities, based on the AIC form factor (half height, half length).
Throughput figures are quoted as up to 5GBps (read) and 3GBps (write), with some variance based on the model/capacity. All deliver up to 850,000 4K IOPS (read) and between 50,000 to 150,000 4K IOPS (write).
It’s interesting to note that write performance reduces with capacity. The DC P3608 Series is based on 20nm MLC Nand flash technology, delivering 3 DWPD (device writes per day – i.e. how many full device writes the hardware can handle over a nominal three- or five-year lifespan).
Memblaze is a PCIe SSD supplier based in China. In 2015, the company was new to our roundup with their PBlaze 3 range of products.
In May 2015, Memblaze released its next generation product, the PBlaze 4, supporting NVMe 1.2 and PCIe 3.0.
The PBlaze4 C/D750 models (based on PCIe 3.0 x4) offer up to 3.2TB of capacity with 3.0GBs (read) and 2.0GBps (write) performance. Latency figures are quoted at 90μs/20μs (read/write).
The PBlaze 4 C950 (based on PCIe 3.0 x8) provides 6.4TB of capacity with slightly higher throughput figures of 3.4GBps (read) and 2.5GBps (write) at the same 90μs/20μs read/write respectively.
Both product ranges are based on Toshiba MLC Nand technology and offer an endurance of 3 DWPD (device writes per day).
Micron has no new product updates since the 2015 review. The company continues to offer the P320h and P420m product lines based on the AIC (add-in card) and 2.5” drive form factors.
Micron has been focused on a partnership with Intel in developing 3D XPoint (a new persistent memory technology), as well as 3D Nand, which should start to appear in products in the near future.
SanDisk continues to offer products based on the technology from its acquisition of Fusion-io in 2014.
The PX600 series continues, with device capacities up to 5.2TB based on PCIe 2.0 x8. Performance characteristics are quoted as 2.7GBps (read) and 2.1GBps (write) with up to 285,000 4K IOPS (read) and 385,000 4K IOPS (write), all with 92μs/15μs latency (read/write respectively).
The SX350, targeted at read-intensive workloads (meaning lower endurance) offers capacities from 1.25TB to 6.4TB.
Performance figures deliver a consistent 2.8GBps (read) with a range from 1.3GBps to 2.2GBs (write) depending on the product model. Devices deliver up to 285,000 4K IOPS (read) and 385,000 4K IOPS (write) at a consistent 79μs/15μs latency (read/write respectively).
Sandisk’s products still do not support NVMe, instead using the virtual storage layer (VSL) technology developed by Fusion-io.
Samsung offers a wide range of consumer and enterprise-based flash products. In the PCIe SSD space, the company has refreshed previous products and released a range of NVMe-based models.
The PM1725, announced in October 2015, uses PCIe Gen3 x8 and offers capacities of either 3.2TB or 6.4TB. Throughput is quoted at up to 6GBps (128KB sequential read) or 2GB (12KB sequential write) with up to 1 million 4K IOPS (read), 120,000 4K IOPS (write). The PM1725 uses Samsung’s 3D V-Nand TLC technology, yet still manages to deliver 5 DWPD (device writes per day).
The PM953 also uses 3D V-Nand TLC technology and supports capacities from 480GB to 1.92TB in either PCIe 2.5” or M.2 formats. Performance figures quote up to 1GBps (128KB sequential read), 870MBps (128KB sequential write) with up to 240,000 4K IOPS (read) and 19,000 4K IOPS (write).
Seagate has refreshed and extended its Nytro PCIe SSD product line, developed from the acquisition of the LSI flash business from Avago Technologies in 2014.
The XP6500 range replaces the XP6200 models and was announced in August 2015 with Nytro XF1440 (2.5”) and XM1440 (M.2) products.
The XP6500 offers either 1.5TB or 4TB of capacity supporting PCIe 3.0 x8 and is based on MLC Nand flash. Throughput figures are quoted as up to 4GBps (read) and 2.2GBps (write) at 200μs (read) or 14μs (write) latency. This translates to around 300,000 4K IOPS (read) and 100,000 4K IOPS write.
Seagate quotes endurance based on overall write capacity, with 8PB for the 1.5TB model and 20PB for the 4TB version – or less than 3 DWPD (device writes per day).
Seagate’s XF1440 and XM1440 series are available as either endurance- or capacity-optimised models. All are based on eMLC technology, using PCIe Gen3 x4 and NVMe 1.1b.
The endurance-optimised models offer capacities from 400GB to 1.6TB and 3 DWPD, compared with capacity-optimised devices from 480GB to 1.92TB with only 0.3 DWPD.
Maximum performance figures for the endurance models deliver 235,000 4K IOPS (read) and 40,000 4K IOPS (write) with 2.5GBs (12KB read) and 900MBps (write) throughput. Latency figures aren’t quoted.
Read more about PCIe flash
- We run the rule over PCIe SSD and assess its potential as a server-side alternative to all-flash storage, as cache in conjunction with shared storage and in hyperscale environments.
- PCIe flash can offer lower latency than array-based flash in some cases. However, it has limitations. Find out if PCIe flash storage is right for you.
Factors that affect NAND memory wear-out