Standards group SSIA has published a new version of the Open19 rack standard, designed to create a standard approach to data center racks featuring liquid cooling, 48V DC power distribution and other advanced features.

The Open19 v2 specification includes a pluggable liquid cooling standard for rack-mounted servers, and a 48V native power solution, which the group says is more efficient than traditional 12V power solutions. SSIA (the Sustainable and Scalable Infrastructure Alliance) was founded as the Open19 group in 2016, and rebranded earlier this year.

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"Open19 is really about aligning around a consistent enough form factor that will allow innovation in this space," said My Truong, SSIA Chairperson and field CTO for Equinix, in a conversation with DCD.

The specification covers the system architecture and "brick" mechanical specifications of racks. Truong explained that the interfaces for liquid cooling were defined to allow even incompatible cooling systems to be "interoperable." Valved connectors for liquid will be defined tightly enough to allow different vendors' equipment to connect but will be able to handle different fluids so that a GPU server cooled by one vendor's technology can be replaced by one using a different cooling system.

In the power distribution part of the specification, a similar level of interface definition will make 48V power distribution easier to deploy without getting caught into a single vendor implementation.

The SSIA was founded as the Open19 group, an alternative to the Open Compute Project (OCP), an open-source hardware body launched by Facebook in 2011

Open19 group began with an alternative rack standard in 2016, complementing OCP's Open Rack, which was designed for hyperscale providers. Open19, developed at LinkedIn, was aimed at smaller parties including telcos and colocation players. OCP wanted to change the internal rack design dimension to 21 inches, and Open19 wanted to innovate within the traditional 19-inch space.

Open19 merged into the Linux Foundation in 2021, and expanded its goals to other areas of data center efficiency.

The latest version includes a pluggable liquid cooling standard, 48V DC native power solution, and capacity to support coming generations of power density.

"V1 of the platform allowed for highly flexible rack deployments per customer or rack-by-rack while retaining the efficiency and cost benefits of an integrated hyperscale solution," explains the SSIA's announcement. "V2 of the Open19 platform is built on this shared form factor with a focus on more efficient power conversion and distribution."

Yesterday, Equinix (where Truong is Field CTO) announced that it would be rolling out direct-to-chip liquid cooling according to the Open19 v2 specifications in more than 100 of its data centers

The open source Open19 v2 specs are available here.