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> Also, why batteries in a datacenter? Everything serious in the telecom/ISP infrastructure sector has a big -48VDC battery plant, or preferably separate A and
by walrus01 4y ago
> Also, why batteries in a datacenter?
Everything serious in the telecom/ISP infrastructure sector has a big -48VDC battery plant, or preferably separate A and B side -48VDC battery plants, to provide a significant buffer between power going Grid --> AC-to-DC Rectifiers --> Equipment, and when a generator can start up, warm up, and transfer switch does its job.
Even if a bunch of servers don't have any UPS or battery backup because they're designed to tolerate individual node (or whole rack, or whole row failures) the core network equipment in a datacenter will still have a huge battery plant.
Ideally if you have a chilled water loop for cooling you do not want it anywhere near your big-ass racks of batteries. Or near the racks that contain the rectifiers and DC breakers, distribution bus bars.
If you look at the battery racks in a traditional telco CO in the US for instance you will see that all of the cabling and batteries are a minimum of 1 foot off the floor, so that the whole place could theoretically flood and the DC distribution would remain unaffected. Same principle that applies to very traditional setups with wet-cell 2V lead acid batteries also applies to more modern things if building from scratch.
- eep_social 4y agoVery different trade offs in play for google who run with a relatively high tolerance for failure at the individual machine or even rack level. At one point I believe there were batteries in every rack, though I don’t know what they're building these days. A telco DC is gonna have more network interconnect with lower tolerance for failure due to capacity impact that isn’t easy to double. Think like a fiber termination demarc vs an in-cluster mesh.
- manquer 4y agoGoogle cloud cannot run high tolerance failures . Google the product wouldn’t notice region or zone going down , google cloud customers will .
- walrus01 4y agoWhat I was saying above is that the 'core' of a google DC has a massive amount of network interconnect and needs for battery backup not very different from a big IX point or traditional "primary CO" for a city in a telco environment. By square footage maybe 95% of a google DC might have no UPS or battery backup but the core network for things like routers and DWDM transport equipment absolutely will have such. If they were unlucky enough that the burst cooling loop met with the battery plant for the core gear in a building or small campus of buildings....