FMS: PCIe switches from copper to fiber - at least sometime soon
Kioxia showed a PCIe 4.0 SSD with fiber optic connection, PCI-SIG demonstrated PCIe 6.0 - and Cadence even showed version 7.0.
Initial demos of a Kioxia SSD connected via fiber optics indicate that there is no loss of speed.
- Lutz Labs
PCIe 7.0 and subsequent versions require optical interfaces for longer connections, 128 or even 256 Gbit/s are difficult to realize with copper cables. At the Flash Memory Summit (FMS) in Santa Clara, California, the first demos with fiber optic connections were presented.
An SSD with an optical PCIe connection was on display at Kioxia, but only in the form of an adapter card for a standard SSD. Kioxia demonstrated that there is no difference in speed between an SSD connected via 40 meters of optical fiber and a locally connected SSD. However, the SSD only worked with PCIe 4.0.
Kioxia also described a scenario in which long optical connection cables make sense: This would allow SSDs and servers to be located in different rooms. As SSDs can withstand higher temperatures during operation than servers, they can run in warmer rooms. This reduces the amount of cooling required and the data center's CO2 emissions.
6.0 and more
The guardians of the PCI specifications, the PCI-SIG, were represented at a joint stand together with other standardization organizations such as SNIA and NVMe.org. There, the PCI-SIG demonstrated the transmission of a PCIe 6.0 signal via optical fiber. Protocol analyzers and recorders from Cadence were used to analyze the transmitted data.
At its own stand, Cadence showed the first demos with PCIe 7.0 using a test card with an optical loop connection at the end. Although the fiber optic cable was only 10 cm long, the manufacturer of test systems showed that a speed of 128 Gbit/s via one fiber is definitely possible.
First 6.0 SSD already planned
Micron announced during the FMS that it is already working on the development of a data center SSD with PCIe 6.0. However, the company has not yet revealed any more details than the speed: the SSD is expected to achieve 26 GByte/s when reading large files. Data on accesses to random addresses is not available, but if you take the peak values of the SSDs presented here and extrapolate them, then more than 5 million IOPS is not unlikely. (ll)
