Concept of a 1U/2U JBOF unit using E1.L enterprise SSD form factor
Disclaimer: I'm not an engineer in this field. This is just a concept. If you have opinions or thoughts, feel free to share them in the "Discussions" tab.
All trademarks, product names, and brands referenced (Solidigm, Supermicro, etc.) belong to their respective owners. This project is unaffiliated and non-commercial.
Publishing date: 19/06/2026
Last edited: 11/07/2026
Core idea:
The core idea is to enhance the storage density in smaller formats like 1 and 2U. This idea is based off of the fact no one has built something like this to this day. JBOF units like the Supermicro petascale are example this can work, even if their models use U.3 and U.2 SSD form factors.
Front:
In the front there are hotswap bays to easily access the drives without pulling the whole rack out like a drawer, making serviceability fast and convenient even when the unit is powered. By putting the E1.L vertically we have 32 slots plus the space for decent airflow.
The 2U variant has an additional row of slots bringing the total up to 64 slots, with the added benefit of using larger 80mm fans to reduce noise and move more air.
Internals:
A singular E1.L is from 9.5mm to 15mm thick, 38.4mm wide and 318.75mm long. By using the 9.5mm variant we can achieve a 32 slots layout in 1U and 64 slot layout in 2U. For cooling in the 1U layout 40mm fans would be used, while for the 2U 80mm fans would be used as previously specified. Liquid cooling could also be used, but for this specific form factor and configuration it's not worth doing. As of now at least.
The backplanes would be 8 four slot PCBs to keep things simpler, so one PCB has to accomodate 16 PCIe lanes (1 E1.L is PCIe x4 so 4*4=16).
For the 2U variant the backplane layout changes, passing from one row of four slots to two rows of two. With the added benefit that a PCB with the 2x2 layout still handles the same 16 lanes.
To merge 128 PCIe lanes in the 1U and 256 PCIe lanes in the 2U, several weaker PCIe switches could work in parallel, or alternatively a single more powerful switch could be used. Additionally a DPU (Data Processing Unit) can be used to handle networking and security. The DPU will add cost and more power being drawn but also allows the JBOF to do more things.
For power in the 1U I'd use a 2+2 configuration (2 PSUs are on, 2 PSUs are on stand-by) and 1000-1400w CRPS, to ensure stable and reliable power delivery since the drives alone draw around 800w. Plus we have to account for other components such as fans, PCIe switches and DPUs.
In the 2U I'd go with the same 2+2 configuration but using 1800-2000w CRPS modules. This is because since the number of drives is doubled, the power draw is also doubled. This takes the power draw to 1600w for just the drives, before accounting for fans, PCIe switches and DPUs.
Connectivity:
I'd reccomend using 2-6 QSFP/QSFP-DD modules, so that the module inside can be changed depending on needs. This covers anywhere from 100GbE to 800GbE. Alternatively standard RJ45 and SFP+ can be used to ensure backwards compatibility with other systems lacking QSFP ports.
For the QSFP/QSFP-DD ports layout I'd suggest putting them side by side, if it's only 2, and stack them if you have 4 or 6, creating either a 2x2 or 2x3 layout. For SFP+ and RJ45 I'd suggest stacking them in a similar layout since one probably doesn't need more than 2-4 SFP+ and RJ45 ports.
Various ports can be chosen based on the intended use of the unit and the form factor (1U or 2U).
Data density:
Thanks to SSDs like the Solidigm D5-P5336 a capacity of 3.9PB per unit can be reached (122.88TB per SSD), though it's only for Gen.4 PCIe. For more IOPS the D7-P5520 is the alternative, however it has a limit of 15.36TB per unit so the total comes out to 491.52TB per unit.
In the 2U the numbers double going up to 7.8PB for the D5-P5336 and 983TB for the D7-P5520.
Optionals:
1-2 small batteries to use as UPS (Uninterrupted Power Supply) to have extra time to safely shut off the unit in case of an emergency, if a UPS isn't available or for small power outages that could damage the hardware if a UPS was absent. The battery/batteries would be located at the back near the CRPS modules to allow serviceability and replace them in the event one was failing due to age, use or other factors.
A small LCD diagnostic display able to show temps, power draw, drive status, connection speeds and errors. This display can be pulled out the front panel through a small tab and once you're done it can be pushed back in. Situated in the bottom right or top right corner of the unit.
Conclusion:
The 1U variant is the more cost effective options that's similar to other options already available with different NVME form factors, while the 2U is the one that takes data density to an extreme but also costs more.
Links:
Solidigm D5-P5336: https://www.solidigm.com/products/data-center/d5/p5336.html#form=E1.L%209.5mm&cap=122.88TB
Solidigm D7-P5520: https://www.solidigm.com/products/data-center/d7/p5520.html#form=E1.L%209.5mm&cap=15.36TB
Supermicro petascale: https://www.supermicro.com/en/products/jbof
My other repo: https://github.com/Monster-Head/High-density-JBOF-server-racks-concept-for-AI-and-Hyperscalers
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
