Wednesday, October 24, 2012 · Posted by pete at 9:02 AM
Most companies lease space in data centers instead of building their own; this isn't news to anyone in this space. But what might be news is that leasing space isn't a barrier to deploying highly efficient Open Compute Project servers. In fact, there are two ways you can use OCP hardware in a co-lo:
- Deploy servers in Open Racks
- Retrofit 19" racks to accommodate OCP servers.
Deploying OCP Triplet Racks
In general, data center operators don't care what hardware you deploy as long as it's not too divergent, so you should be able to deploy an OCP triplet rack into a co-located facility. If you want to use triplets, consider the following items before you do so:
- Height. At a little under 95" tall, the triplet rack should fit into most data centers.
- Weight. A fully loaded triplet weighs 2600 pounds (1179kg). If you want to deploy an OCP triplet cabinet, you should verify the weight limitations of the floors in your facility.
- Battery cabinet weight (in the event you can use the OCP battery backup cabinet in lieu of your facility's backup power system). As with the triplets, the battery cabinet height is standard, but it weighs 2220 pounds (998kg) fully loaded. Check the weight limitations of the floors in your data center.
Retrofitting the 19" Rack
Before the Open Rack was completed, Facebook deployed OCP v2.0 servers in several suites at one of its leased data centers. The process took about 3 months from design to deployment.
Because we were deploying the servers into rooms designed for standard 19" racks, we ended up slightly modifying the standard rack to suit our needs. Surprisingly, the implementation required only a few modifications from the OCP specifications before we deployed it:
- A modified server rack, to support the OCP v2.0 servers. We took DAMAC's standard 19" rack (rails and all) and riveted two shelves and side panels from an OCP triplet to it, to provide the right-angle tabs that can accommodate the OCP v2.0 chassis.
- New power strips on the server racks, since we're running off the data center's 208V power instead of the OCP 277V. We bought off-the-shelf strips from Server Technology. Some racks used both master and slave power strips, while others used only the master (the part number is for the master power strip is CS-24VYM313, the part number for the slave power strip is CL-24VYM313).
- New power cords connecting the OCP power supply to the new power strips. We used a Tyco main lock to a standard C-13 connector.
- The facility has its own battery backup power, so we didn't use the OCP 48V battery backup system.
Everything else stayed the same. We used a standard, vanity-free OCP v2.0 server with no changes whatsoever, including the power supply. The power supply is rated down to 190V, so powering the servers with 208V is still within the normal operating range. But at 208V, the current needs to increase to keep constant power, which makes the power supply a little less efficient (94.4% efficient) than when it's running at 277V.
As you'd expect, the servers operate at higher power conversion efficiency than non-OCP servers. The 60mm fans brought about the same thermal efficiencies. The inlet temperatures were cooler than those found in Facebook-owned facilities, but the fans adapt and run more slowly without any changes on the fan controls.
The racks have the same serviceability improvements, but fit easily into a co-located facility. The single-column design made for easier maneuvering of the racks in the data halls.
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Update January 30, 2013
We just published a specification on how to do this.