pjdesno
Joined 6 years ago
Joined 6 years ago
In particular you can still get used Optane SSDs on eBay, although they’re fairly pricey. (not the bogus m.2 ones that are slower than a halfway decent consumer NVMe)
I was a VMware workstation user in the late 90s.
I worked on the VMware monitor team back in 2007-2008, which probably put my employee number way in the 1000s. Ole Agesen, Carl Waldspurger, and other early folks were still there.
Back then "kvm" meant a remote keyboard/video/mouse device. Linux kvm was announced in 2006, and released in 2007, and required hardware virtualization, which was first released with AMD Pacifica in 2006. Back then VMware's binary translation was locked up in patents, so in the free software world we had Xen, colinux, and other hacks.
This is a bug involving intersecting concerns and a deficit of cross-domain knowledge. It probably would have been the same in Lisp or assembly language.
Some of the folks looking to build datacenters to cash in on the AI craze aren't as bright as that.
My point is not that evaporative cooling is necessary - it's that it's efficient, and therefore common. I found some 10-year-old info from our datacenter, and it looks like mid-summer months add an extra 20% in power consumption for cooling, in large part due to running the chillers, which are industrial-scale active A/C units to raise the exhaust heat temperature. Average outdoor temp (24-hr average) during those months was 70-75F.
It's a pretty small datacenter, so getting rid of the evaporative cooler would probably "only" cost us a couple of megawatts or so in additional power consumption. (and maybe 15 million pounds of carbon emissions - our power is hydro, but electricity is fungible, so every kWh we use probably results in an additional kWh of fossil fuel generation somewhere in the grid)
Those that do - power generating facilities, large smelters, etc. - have very significant environmental footprints.
Historically, cooling alone has accounted for up to 40% of a data center’s electricity consumption
The key word here is "historically". Modern data centers typically have a PUE lower than 1.2, with the .2 including not only energy spent on cooling but power distribution losses as well.Our data center is mostly air-cooled, with 100F hot aisles and chilled water going to heat exchangers in every third rack position, although some of our newer GPU racks use chilled water directly. For most of the year that means we don't need chillers - the warm water return is sufficiently hotter than outdoor temp that heat "flows downhill" with a bit of pumping.
But we use an evaporative cooler to carry that heat away outside, because it's more efficient. If you look up the heat of vaporization of water, that means we evaporate about 10,000 gallons of water per day per megawatt of power dissipated. We're on canal off a large river, and we don't dissipate all that many megawatts, so I believe the water use isn't significant.
Using air as the working fluid to draw heat from your machines has a limitation - humans have to breathe that air whenever they work on the equipment, so the temperature is limited. Once the exterior temperature nears your hot aisle air temp, you either need active A/C to create a heat source hotter than ambient, or an evaporative cooler to lower the "effective" ambient temp to the dew point.
Liquid cooling lets you run your working fluid a lot hotter without killing folks like me who go into the data center, although honestly 45C sounds like an incremental improvement over the 100F places like ours are already running. (although to be fair, the warm water return from the heat exchangers is no doubt somewhat less than 100F) It also lets you run your "cold" side a lot hotter - if you "chill" your water down to 100F (38C) on a hot day, it's still cold enough to carry away a lot of heat at 45C.
(I'm skipping over the fact that there are multiple heat exchanger loops involved - e.g. any system with an evaporative cooler needs a heat exchanger to keep leaves and bird shit outside the building where it belongs)
I don't care about service at a gas station - I want to fill my tank, pay, and get out. It's different when I take it to the mechanic - it's a rather old car, and I appreciate them talking intelligently about what the options are and what repairs they would suggest.
There's one exception to this - HAMR added additional components, and a corresponding increase in BOM cost, but there's probably a learning curve on this.
However the recent AI data center boom is probably hitting HDDs in two ways - (a) general demand for anything datacenter-related, and (b) high DRAM prices, with most HDDs containing 256-512MB of DDR3. (I haven't physically examined the newest drives - they may be DDR4 and go beyond 512MB; also the 40TB supposedly includes NAND flash, adding yet more cost)