We had a tremendous response to our webcast asking if we were truly at the end of the 2.5-inch disk era. SNIA Compute, Memory, and Storage Initiative SSD Special Interest Group brought together experts from Dell, Facebook, HPE, JEDEC, KIOXIA, Lenovo, and Microsoft in a lively follow on to the Enterprise and Data Center SSD Form Factor (EDSFF) May 2020 discussions at OCP Summit,. If you missed our live webcast – watch it on demand.
Webcast attendees raised a variety of questions. Our experts provide answers to them here:
Q: SFF_TA_1006 suggests E1.S can support max 25W for 25mm asymmetric heat-sink. What are the air-flow assumptions for this estimate? Are there any thermal models and test guidelines available for EDSFF form-factors?
A: Yes! The SNIA SFF TA TWG has a new project on Enterprise Device Form Factor Thermal Requirements. There was a great presentation about this at the OCP 2020 Virtual Summit. Registered attendees can log in to view.
Q: When is the transition form U.2 to E3 expected to occur?
A: We expect a few products for PCIe 4.0 but a wide industry transition at PCIe 5.0
Q: No one is mentioning dual-path. Is this an Enterprise requirement and does EDSFF connector support this?
A: EDSFF does support dual port and enterprise storage high availability applications, with a dual port enable pin, if the SSD vendor supports it.
Q: What is the future vision as to fault tolerance options (RAID, mirroring, etc) for these devices in data center use cases in a way that doesn’t compromise or bottleneck their performance? HW raid controllers could bottleneck on PCIe bandwidth as one speaker mentioned, and SW RAID or virtual SAN solution overhead + application workloads could bottleneck on CPU before you’re able to max out storage performance (especially at these extreme density possibilities, wow!). Thanks!
A: SNIA just did a webcast on NVMe RAID!! See it in our Educational Library:
RAID on CPU RAID for NVMe SSDs without a RAID Controller Card
Q: For open frame drives, is a Bezel required for EMI containment?
A: Yes, a latch is expected to have some EMI design
Q: Do all EDSFF form-factors support hot-plugging? Can EDSFF physical form-factors support all capabilities defined in NVMe (storage) specification?
A: Yes, hot plug is expected on EDSFF drives and is included in the SFF-TA-1009 pinout spec for support (interface and presence detect pins).
Q: Can a 2U system plug 2xE1.S into the same bay as 1xE3.S can be inserted?
A: This would require a custom PCB or carrier card. A single E1.S is electrically compatible with an E3 slot.
Q: If the ‘1’ in E1.L and E1.S means ‘1 Rack Unit’ what does the ‘3’ in the E3 family means since it is compatible with 1U and 2U?
A: Correct, E3 was originally for “3in media device” intended to be optimal for 2U vertically oriented, or a 1U horizontal.
Q: Can you estimate the shipment volume share for each form factors? Especially I’d like to know 70W E3.L shipment units forecast.
A: As an example, Intel has publicly stated that they expect up to 35% of the data center SSD revenue total market to be on EDSFF by 2024. Analysts like Forward Insights have detailed EDSFF and SSD form factor market analysis.
Q: No one is talking about shock and vibe for this connector. Is this an exercise for the carrier designer?
A: Mechanical specifications are expected to be similar to U.2 drives today.
Q: With the 2.5″ challenges, and migration to other form factors, what about client systems? It would seem the x4 interfaces would work just fine on a desktop, and the slimmest E1.S on a laptop for better heat dissipation.
A: Many people think M.2 will not be adequate for PCIe 5.0 speeds and power, and companies are looking at reusing E1.S or another client EDSFF variant with the same connector as a successor for desktops and workstations.
Q: Is there a detailed standard of SSDs configuration with different device types, and once there is an error, could SSDs be combined to solve the error problem?
A: SSD data protection is generally solved with RAID, software mirroring, or erasure code.
Q: When will volume servers support the new form factors/connectors?
A: We already see production servers for EDSFF from Supermicro, Wiwynn, AIC, and announcements from Lenovo and others launching soon!
Q: Is U.3 dead?
A: U.3 means conforming to the SFF-TA-1001 link definition specification for the SFF-8639 connector. It isn’t a form factor definition like EDSFF, and it applies to U.2 (2.5” form factor) drives used with a Tri-mode HBA and properly enabled system backplane. Read more about U.3 with this article.
Intel and other suppliers are transitioning from U.2 & M.2 directly to EDSFF, bypassing support for U.3. Some companies are supporting U.3 technology through servers, HBAs, and SSDs.