Pod Power Consumption

[Rick Peralta]

Are there numbers on the quiescent, average and peak power used by a POD?
And maybe the total power budget of a POD server room and it's storage capacity?
And the relative usage percentages in each mode?

Cheers,

 - Rick "Once the door is open" ;^)

[jason andrade]

G'day Rick,

I'm also interested in this in terms of 'real data' but taking a stab at answering this using available data.

The OSP 5.0 is specified to use 2 x 750W power supplies.

From what I can tell, these are actually redundant but distributed power usage (rather than aggregated) so the most power you should be pulling is 750W from a chassis.

If you specify that a drive uses 8W of power (at peak) and 6W (at idle) then you can approximate 45 drives are going to use 360W/270W.

360+360 = 720W (which doesn't leave much room at all for the motherboard, cpu, ram, cards, boot disk) so let's figure that in the event of PSU you aren't going to be able to run these flat out.

270+270 = 540W which leaves some room for the system overhead in the event of a PSU failure if the system is idle

If they are 4RUeach and you use 42RU racks, you could assume either 5 or 10 in a rack (20RU vs 40RU).

5 of these at approximately 700W would be 3.5KW or 7KW in a 'full' rack.  This is relatively dense for a corporate/enterprise deployment but really no big deal for a HPC or otherwise specialised DC environment (we can see 20kW+ in some racks).

It'd be interesting to see how far out I am from projected figures and assumptions compared to the reality.

In summary:

Around 700W per unit average use?
7KW per rack (10 pods)
14kW per 'Vault" (20 pods)

at $0.3 per kWH

$5 per pod, per day (180T raw storage)
$1840 per pod, per year (365 days)

$50 per rack, per day (1.8P raw storage)
$18,400 per rack, per year

$100 per vault, per day (3.6P raw storage)
$38,800 per vault, per year

If i'm out by a factor of 2 (i.e i've underestimated the actual power draw by 50%) then double every figure of course.. 

If you work backwards from BB having > 100P (assuming raw), that's almost 30 vaults worth..  or a power bill in the order of $1.2m/year

At which point, if you can figure out a way to save 10% on your power you are making reasonable savings..  (without even thinking about carbon costs on top of this as well).

regards,

-jason
-----
M: +61 402 489 637   E: jason....@gmail.com

--
You received this message because you are subscribed to the Google Groups "OpenStoragePod" group.
To unsubscribe from this group and stop receiving emails from it, send an email to openstoragepo...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[jason andrade]

G'day,

Ran through those numbers with a colleague at work and obviously I did make at least one glaring error.. oops.

Where you have 45 disks at 8W, that's a total of 360W (at peak usage) and as such, that fits fiarly comfortably into one PSU leaving another 390W available for the motherboard, cpu, ram, controller cards, fans and boot disk. Where you have two PSU then that's more than enough capacity to run flat out on either one..

So basically I think it's still ~700W being a rough estimate per pod.

What's puzzling is seeing some other posts that reference a pod needing 1500W of power (for 45 disks) so either something has become more efficient between the gen1 of the pod or other people had wires crossed as well.

[Matthew Patton]

The only sane way to run this is as 'throw-away' nodes where if the node has a component failure (MB/CPU/PS) it's just dead until repaired and not bother with HA. Even better to intelligently power-manage the disks, first by knocking the RPM down, then stopping the motor. You can also turn off the board, but I doubt that last level of power savings is worth bothering with.

But of course this means the storage service isn't implemented in a naive manner.

Amazon runs their S3 and Glacier fleet on a single power supply (1350W or was it 1500W) to run >85 disks per enclosure. The head unit is also single PS, single ethernet. Glacier only has ~1/4 of the drives in a rack powered up because otherwise they'd blow the breaker. They rotate which disks are on and when with their scheduler.

[Rick Peralta]

Without hard numbers it is hard to realistically conside options.  We have anecdotal information on power usage, but they are only speculation.  Who knows what the active, idle and suiescent power usage levels are?  What is the duty cycle for each?

And what is the total power usage of the machine room, including supporteing communcations, HVAC, lighting et cetera.

Fine tuning the existing technology is a way to tweak a few percentage improvements.

Changing the fundamentals of how the storage is done can provide mulh greater improvements.

But before makig changes, one needs to know where you stand...

Cheers,

 - Rick

--
You received this message because you are subscribed to a topic in the Google Groups "OpenStoragePod" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/openstoragepod/XviEc_uULQU/unsubscribe.
To unsubscribe from this group and all its topics, send an email to openstoragepo...@googlegroups.com.