6500 ION TLC and XTR SLC

Micron is increasing its knowledge heart SSD lineup at this time with the introduction of two new merchandise – the 6500 ION and the XTR NVMe SSDs. These two merchandise don’t fall into any of their present enterprise SSD lineups. They’re meant to fill holes of their product stack for high-capacity and high-endurance choices.

Micron’s opponents have high-density QLC choices in quite a lot of type elements for datacenters aiming to maximise the per-rack storage capability. However, after the discontinuation of Optane, Micron wanted a storage-class reminiscence different for write-intensive workloads. Micron’s present product stack has choices for each the mainstream and efficiency NVMe classes within the type of the 7400 collection and 9400 collection respectively. The 2 SSDs being launched at this time handle the high-capacity and high-endurance market phase.

The Micron 6500 ION NVMe SSD addresses the high-capacity side. It’s a TLC drive with QLC pricing. The Micron XTR NVMe SSD addresses the excessive endurance side. Regardless of not being a low-latency play, its function set makes it aggressive in lots of metrics in opposition to SCM-class merchandise. A more in-depth take a look at the specs and market place of the 2 SSDs together with a dialogue of the aggressive panorama follows.

The Micron 6500 ION TLC NVMe SSD

NAND flash know-how has developed quickly within the final decade or so, with the transfer from low-density planar SLC to MLC, after which on to TLC. The appearance of 3D NAND has now enabled quad-level cells (QLC) that encode as much as 4 bits of knowledge in a single cell utilizing 16 totally different voltage ranges. This enables a dramatic improve in capability for a given die space. QLC comes with its personal share of challenges, and is worse than TLC from the point of view of just about all metrics – efficiency, endurance, and energy consumption. QLC flash is primarily a value play for each the patron and the seller within the consumer SSD market. Within the enterprise space, value is one issue, however the extra fascinating one is rack density. QLC SSDs within the final couple of years have breached the 30TB capability level at cheap costs, permitting for a single rack to carry upwards of 1 PB.

Sizing up the Competitors…

Micron’s QLC play within the enterprise market has been muted. However, its competitor, Solidigm, has been extraordinarily bullish on QLC for knowledge heart use. The Solidigm D5-P5316, specifically, has proved in style from this angle. A 30TB+ drive in a 2.5″ (U.2) form-factor at lower than $100/TB has proved to be engaging for knowledge facilities to drive up per-rack capability. As per Solidigm’s personal advertising and marketing materials, there isn’t a free lunch. QLC does include downsides by way of gradual sustained sequential writes (in comparison with TLC). The D5-P5316 additionally opted to extend the indirection unit from 4K to 64K. Whereas this enables simpler flash administration, 4K random writes are significantly impacted as a result of latency improve from repeated entry to the indirection desk in addition to extreme write amplification. The latter leads to very low endurance (by way of random drive writes per day).

Supply: Empowering Actual-Time Resolution Making for Massive-Scale Datasets with SSD-like Economics, SNIA Persistent Reminiscence + Computational Storage Summit, 2022

The Solidigm D5-P5316 can maintain sequential writes (direct to QLC) of simply 3.6 GBps, and 4K random write efficiency is just 7800 IOPS. Nonetheless, the numbers are extra cheap for 64K random writes due to the indirection desk. Solidigm truly suggests adapting the software program to keep away from 4K random writes, or utilizing the drive just for workloads which might be both read-intensive or with massive block sequential / random writes. These sorts of workloads significantly decrease the I/O amplification, this addressing the endurance side. Regardless of these shortcomings, the rack density alternative was simply too good for the info facilities to go up. Micron sadly didn’t have a similarly-priced different at that capability level. That modifications at this time with the 6500 ION.

Avoiding QLC

Micron was the primary to ship 3D NAND with 200+ layers, with its 232L technology reaching high-volume manufacturing properly forward of its opponents. The corporate has been utilizing QLC within the consumer SSD marketplace for some time now. Nonetheless, it has been a bit reticent to make use of it in enterprise SSDs, and the explanations should not obscure. After the dissolution of the IMFT joint improvement program, Micron and Intel / Solidigm adopted diametrically different flash cell architectures. Whereas Intel / Solidigm continued with floating gate know-how, Micron moved on to the cost lure scheme.

Typically talking, Micron’s cost lure flash cell structure is extra suited to TLC. Utilizing it for QLC is tougher in contrast to what’s doable with Solidigm’s floating gate method.

Supply: The Benefits of Floating Gate Know-how (YouTube)

Floating gates have lesser cost dispersal points, and extra electrons, permitting for higher knowledge accuracy over time – significantly when 16 totally different voltage ranges must be tracked.

Finish product value for high-capacity SSDs is generally dominated by die value for the flash. Based mostly on the evaluation here, Solidigm’s 144L QLC had a bit density of 12.86 Gb/mm², whereas Micron’s 232L TLC’s equal quantity is 14.60 Gb/mm². With QLC, this quantity may go even increased. It’s doable for Micron to have used 232L QLC to create a good cheaper 30TB SSD in comparison with the Solidigm D5-P5316, however its specs by way of endurance and speeds would have in all probability been much like (or worse than) Solidigm providing because of the nature of the flash cell.

Micron determined {that a} high-capacity 232L TLC SSD may very well be priced competitively in opposition to the 144L Solidigm D5-P5316 QLC providing. This resulted within the improvement of the Micron 6500 ION NVMe SSD.

Diving into the Particulars

The important thing to the Micron 6500 ION’s promise of TLC efficiency at QLC pricing is its NAND fabrication management. The corporate is focusing solely on the 30.72 TB capability level with the 6500 ION. Different capability factors are served properly by different merchandise in its stack. Using TLC implies that sequential writes can go as excessive as 5 GBps, and a 4KB indirection unit ensures random write efficiency of round 200K IOPS. The lowered write amplification implies that the 6500 ION’s 4K RDWPD ranking of 0.3 is greater than 10 occasions higher than the same quantity for the Solidigm D5-P5316. Micron claims that TLC SSDs are inherently extra energy environment friendly in comparison with QLC ones, and that does bear out primarily based on the comparability of the datasheet of the D5-P5316 and the brand new 6500 ION.

On the enterprise entrance, the Micron 6500 ION is TAA-compliant and likewise FIPS 140-3 L2 certifiable. Just like different enterprise SSDs, the drives carry a 2.5M hour MTTF and a 1 in 10¹⁷ uncorrectable bit-error price.

The Micron 6500 ION SSD brings a compelling choice to knowledge heart prospects who’ve adopted the Solidigm D5-P5316 or actively thought-about adopting it. Nonetheless, Solidigm has not been idle both. Eventually yr’s Tech Area Day, the company had talked about utilizing its 192L QLC know-how to create 30TB SSDs with 4KB IUs. So, the challenger for the 6500 ION out there might be these drives, quite than the Solidigm D5-P5316.

Earlier than shifting on to the XTR NVMe SCM competitor, a word on RAID rebuild occasions with 30TB SSDs is warranted. One of many vexing points with high-capacity HDDs is RAID rebuild with parity computation and writing, with the method being bottlenecked by the SATA interface. Fortunately, the PCIe 4.0 x4 NVMe interface with sequential speeds approaching 6.8 GBps reads and 5 GBps writes, can simply deal with that even when servicing different knowledge workloads. Even when operated in a cluster unfold over a number of bodily machines, utilization of a 50 GbE or sooner community spine can allow this resiliency with minimal efficiency impression.