EDSFF Type Issue Updates In 2020: New Variations, Rising Adoption

The Enterprise and Datacenter SSD Type Issue household of requirements is now about three years previous, and continues to evolve. The EDSFF kind issue choices are gaining traction in a number of markets, and classes realized by early adopters are nonetheless driving tweaks to the specs. The myriad variations beneath the EDSFF umbrella haven’t been simplified a lot, however at the very least the transient format warfare between the EDSFF E1.S kind issue and Samsung’s NF1 has concluded, with Samsung now supporting and contributing to the E1.S customary. As EDSFF adoption will increase, we’ll most likely see a number of variants fall into irrelevance, as occurred to a few of the much less standard M.2 card sizes. However even as soon as it is clear which members of the EDSFF household are succeeding available in the market, the much less standard choices will most likely stay a part of the requirements paperwork.

The EDSFF flavors all share a typical connector customary, which originated because the Gen-Z Scalable Connector Commonplace and has been adopted by a number of different requirements. The Gen-Z connector gives a lot greater density than conventional PCIe slots, provides the 12V energy that M.2 lacks, and is comparatively future-proof by providing satisfactory sign integrity for future variations of PCIe. The EDSFF requirements outline three sizes of the connector and pinouts for PCIe x4, x8 and x16 hyperlinks.

The EDSFF kind components are available two heights: sized for 1U servers are E1.S and E1.L, the brief and lengthy derivatives of the Intel Ruler idea. For 2U servers, the E3 sizes are just like the present 2.5″ drive kind issue.

 

Reboot Of E3

Essentially the most vital adjustments previously 12 months have been to the E3 kind components. Earlier this month model 2.0 of the E3 kind issue spec was printed, breaking backwards compatibility with model 1.0 from 2018. The motivation for the incompatible adjustments got here from the Open Compute Undertaking (OCP) NIC 3.0 specification, which has related dimensions however makes use of a brand new variant of the Gen-Z connector: OCP added a fourth tab with 28 further contacts to hold numerous sideband indicators not included within the 4c (x16) model of the connector. The E3.S kind issue was stretched a bit to match the scale of the OCP NIC 3.0 customary, and the connector location was moved to be appropriate with the OCP NIC 3.0. With the brand new model of the EDSFF E3 spec, it is now doable for servers to supply slots that may fulfill both position.

The E3 kind components are probably the most succesful and versatile within the EDSFF. They assist as much as PCIe x16 connections, although most SSDs will proceed to stay with simply x4. The E3.L 2T affords related bodily quantity and TDP to a half-height half-length PCIe add-in card. The E3.S in two thicknesses is barely bigger than the 2 widespread thicknesses for U.2/U.3 SSDs, however E3.S affords higher cooling and the potential for extra PCIe lanes. The newly stretched E3.S can be now massive sufficient that an E1.S PCB will be mounted inside an E3.S case, offering a fast and simple path for compatibility between the 2 heights.













E3 model 2.0 Type Issue variants

SFF-TA-1008
Type Issue Approximate

Dimensions (mm)
Entrance Drive

Bays in 2U
Typical SSD

Energy Restrict
Max PCIe

Lanes
E3.S 76 113 7.5 48 25 W x16
E3.S 2T 76 113 16.8 24 40 W x16
E3.L 76 142 7.5 48 40 W x16
E3.L 2T 76 142 16.8 24 70 W x16
   
PCIe HHHL 68 168 19   40-75 W x16
2.5″ U.2 7mm 70 100 7 48 12 W x4
15mm 70 100 15 24 25 W x4
3.5″ U.2 (theoretical) 102 147 26 12   x4
M.2 22110 22 110 5   8.25 W x4

When the EDSFF household launched, many of the early consideration was targeted on the E1.S and E1.L kind components as a result of they addressed probably the most urgent wants of hyperscale datacenters. The E3 kind components are extra engaging for conventional enterprise servers, which take longer to undertake adjustments like this. Dell and HPE are the main proponents of this a part of the EDSFF household. For the reason that E3 customary was simply rebooted with an incompatible change, we’re now E3 model 2.0 merchandise hitting the market across the first half of 2022.

Servers utilizing E3 kind components are probably to make use of multiple model, resembling offering a dozen or extra skinny slots for SSDs, plus a number of of the thicker 2T slots for NICs, accelerators, and higher-power SSDs (eg. based mostly on 3D XPoint or another storage class reminiscence). Whereas they’re primarily meant for 2U methods, the E3 kind components can be utilized in 1U servers, however have some cooling and density disadvantages relative to E1.S for 1U methods.

 

 

E.1S In Manufacturing Use

The E1.S household has now grown to incorporate 5 totally different thickness choices. Nonetheless, the requirements for a naked PCB or one with only a heatspreader will not be getting a lot consideration. The three (previously two) variations with a full enclosure appear to be the most well-liked. These can slide immediately right into a hot-swap bay with no need to be screwed right into a tray or caddy. On the entrance of the drive is a flange with two screw holes that are used to connect an applicable latching mechanism for no matter server chassis the drives can be put in into. Samsung has not too long ago proposed modifying this with a number of further cutouts to allow a screw-less model of their latching mechanism, which can be faster to put in.

This 12 months’s addition to the E1.S customary was a brand new intermediate thickness heatsink possibility proposed by Microsoft and meant for his or her Azure datacenters. Microsoft discovered that the 9.5mm symmetric enclosure did not provide fairly sufficient cooling for the sort of drive TDPs they’re anticipating for PCIe Gen4 SSDs (at the very least, inside the bounds of affordable fan speeds), however the 25mm uneven enclosure/heatsink sacrifices a bit an excessive amount of density and has extra thermal headroom that Microsoft would not want for his or her major storage drives. Consequently, there’s now additionally a 15mm model standardized and already being deployed at scale.













E1.S Type Issue variants

SFF-TA-1006
Type Issue Approximate

Dimensions (mm)
Entrance Drive

Bays in 1U
Typical SSD

Energy Restrict
Max PCIe

Lanes
E1.S Naked PCB 32 112 5.9   12 W x8
Heatspreader 32 112 8   16 W x8
Symmetric

Enclosure
34 119 9.5 36 20 W x8
Uneven

Enclosure
34 119 15 24 20 W x8
34 119 25 16 25 W x8
   
M.2 22110 22 110 5   8.25 W x4
2.5″ U.2 7mm 70 100 7 20 12 W x4
15mm 70 100 15 10 25 W x4
PCIe HHHL 68 168 19   40-75 W x16

The 9.5mm-thick enclosure possibility was already adequate to kill off server M.2 drives aside from boot drive utilization: it affords the hot-swap functionality and 12V energy that M.2 lacks, and will be deployed with related density. The newer 15mm thick heatsink model of E1.S could find yourself being extra standard, however it is a bit too new to guage how a lot traction it would get past the unique proponents. In comparison with 2.5″/15mm U.2 SSDs, the E1.S 15mm kind issue remains to be a major enchancment: 4 E1.S 15mm drives can match within the area of two 15mm U.2 drives, and the E1.S drives are nonetheless simpler to chill. Storage-focused methods can obtain greater density with the 9.5mm possibility, however the E1.L kind components provide even greater storage density.

The 25mm heatsink E1.S possibility now appears more likely to be the least standard of the three enclosure decisions. It nonetheless has a distinct segment for squeezing high-power accelerators into 1U methods, however PCB width is usually a limiting issue and the E3 kind components may accommodate massive, high-power chips. Any E1.S slot offering 8 as an alternative of simply 4 PCIe lanes is probably going to make use of at the very least the 15mm heatsink possibility, as a result of an accelerator able to utilizing that a lot bandwidth will want the additional cooling.

All the E1.S variants use the identical PCB and fluctuate solely within the steel enclosure and top of the heatsink (if any), so there’s not a lot burden on SSD distributors to assist all three of the 9.5mm, 15mm and 25mm. Server distributors face the harder alternative of deciding how extensive to make their slots; narrower drives will be mounted in wider slots, however this will result in unbalanced airflow—although not as dangerous as leaving a slot empty and not using a placeholder inserted. The commonest configuration for general-purpose 1U servers may find yourself being a financial institution of E1.S slots for storage plus one or two E3.S/OCP NIC slots—this appears particularly probably if the OCP strategy of placing all IO on the entrance of the server catches on exterior of hyperscale datacenters.

 

E1.L Unchanged

There have been no latest adjustments to the E1.L kind issue. This one stays the closest to Intel’s authentic Ruler idea. It’s for much longer than some other drive kind issue, so the complete server structure should be designed round E1.L. This kind issue can be used virtually solely in methods designed for the only real objective of containing a whole lot of flash reminiscence, and won’t see any vital adoption for general-purpose or compute-oriented servers. E1.L is appropriate for drives with capacities of tens of TB every.








E1.L Type Issue variants

SFF-TA-1007
Type Issue Approximate

Dimensions (mm)
Entrance Drive

Bays in 1U
Typical SSD

Energy Restrict
Max PCIe

Lanes
E1.L Skinny 38 319 9.5 36 25 W x8
Thick 38 319 18 18 40 W x8
   
2.5″ U.2 15mm 70 100 15 10 25 W x4
PCIe HHHL 68 168 19   40-75 W x16

Whereas not formally a part of the EDSFF specs, the Open Compute Undertaking’s storage working group has developed the OCP NVMe Cloud SSD specification. This can be a unification of most of Microsoft and Fb’s necessities for his or her SSDs, protecting areas just like the non-obligatory NVMe options, telemetry capabilities, endurance and efficiency that these corporations need. The Cloud SSD specification applies to M.2 22110, E1.S and E1.L kind components. A number of SSD distributors are already focusing on this specification, which can assist minimize down on the quantity of firmware customization required by totally different prospects.

 

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