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How oxide cuts data center power consumption in half

(oxide.computer)
195 points tosh | 8 comments | 21 Nov 24 18:12 UTC | HN request time: 1.47s | source | bottom
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shivak ◴[21 Nov 24 20:31 UTC] No.42208324[source]▶
> > The power shelf distributes DC power up and down the rack via a bus bar. This eliminates the 70 total AC power supplies found in an equivalent legacy server rack within 32 servers, two top-of-rack switches, and one out-of-band switch, each with two AC power supplies

This creates a single point of failure, trading robustness for efficiency. There's nothing wrong with that, but software/ops might have to accommodate by making the opposite tradeoff. In general, the cost savings advertised by cloud infrastructure should be more holistic.

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1. sidewndr46 ◴[21 Nov 24 21:16 UTC] No.42208751[source]▶
This isn't even remotely close. Unless all 32 servers have redundant AC power feeds present, you've traded one single point of failure for another single point of failure.

In the event that all 32 servers had redundant AC power feeds, you could just install a pair of redundant DC power feeds.

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2. gruez ◴[21 Nov 24 21:52 UTC] No.42209061[source]▶
>Unless all 32 servers have redundant AC power feeds present, you've traded one single point of failure for another single point of failure.

Is this not standard? I vaguely remember that rack severs typically have two PSUs for this reason.

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3. glitchcrab ◴[21 Nov 24 22:00 UTC] No.42209141[source]▶
It's highly dependent on the individual server model and quite often how you spec it too. Most 1U Dell machines I worked with in the past only had a single slot for a PSU, whereas the beefier 2U (and above) machines generally came with 2 PSUs.
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4. sidewndr46 ◴[21 Nov 24 22:14 UTC] No.42209235[source]▶
you could have 15 PSUs in a server. It doesn't mean they have redundant power feeds
5. thfuran ◴[21 Nov 24 22:25 UTC] No.42209325{3}[source]▶
But 2 PSUs plugged into the same AC supply still have a single point of failure.
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6. jeffbee ◴[21 Nov 24 22:43 UTC] No.42209457[source]▶
Rack servers have two PSUs because enterprise buyers are gullible and will buy anything. Generally what happens in case of a single PSU failure is the other PSU also fails or it asserts PROCHOT which means instead of a clean hard down server you have a slow server derping along at 400MHz which is worse in every possible way.
7. glitchcrab ◴[22 Nov 24 07:05 UTC] No.42211740{4}[source]▶
Which is why you have two separate PDUs in the rack which are fed by different power feeds and you connect the server's 2 PSUs to opposing PDUs.
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8. growse ◴[22 Nov 24 20:17 UTC] No.42217051{5}[source]▶
This works brilliantly, right up to the point where your A side fails, and every single server suddenly doubles their demand on B.

Better have good capacity management so you don't go over 100% on B when that happens! (I've seen it happen and take a DC out).