Neal Pollack wrote:
On 07/ 1/09 05:11 AM, Haudy Kazemi wrote:
Ian Collins wrote:
Or run your systems of DC and get as much backup as you have room
(and budget!) for batteries. I once visited a central exchange with
48 hours of battery capacity...
The way Google handles UPSes is to have a small 12v battery
integrated with each PC power supply. When the machine is on, the
battery has its charged maintained. Not unlike a laptop in that it
has a built in battery backup, but using an inexpensive sealed lead
acid battery instead of lithium ion. Here is info along with photos
of the Google server internals:
http://news.cnet.com/8301-1001_3-10209580-92.html
http://willysr.blogspot.com/2009/04/googles-server-design.html
which is of course why people claim that google is less green than
detroit :-)
Each sealed lead-acid battery is good for about 2 years in those power
supplies.
Goodle uses more than 10,000 servers, many more.
Do the math. That's many many tons of lead and acid in the dump every
24 months.....
Yes, but...
Lead acid batteries are one of (if not _the_) the most-recycled items in
the world. Something like 99.99% of all lead-acid batteries get fully
recycled.
Personally, I don't like Google's solution. That's waaaay too many small
batteries in everything. I'd be more in favor of something like a
double marine battery every 2 racks. Lots more power, and those things
are far easier to recondition and reuse - and much less labor intensive
to install than 1 battery in 80+ servers.
All this said, I certainly do agree that the proper thing to do is move
to full 12V DC inputs for all computers intended for data center use.
Eliminating the need for non-12V (i.e. get rid of all the stuff that
want 5V) on the internal components is really needed to make this
efficient; that way, all you need in the way of a power supply is
something that takes 48VDC input, and breaks up the leads into 12V
outputs. Really cheap, really efficient. Having a nice 48VDC bus for
the rack (like Telco) is much more energy efficient and far easier to
hook something like a small UPS to...
--
Erik Trimble
Java System Support
Mailstop: usca22-123
Phone: x17195
Santa Clara, CA
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