[Server-devel] Powering a hard drive?

Anish Mangal anish at sugarlabs.org
Fri Aug 16 20:35:25 EDT 2013


I have been trying to crunch some numbers and the results seem interesting.
I don't claim the calculations to be correct, so if someone with more
knowledge (than me or a quick google search) can reply, would be very

The average difference between power consumption of an SSD and a HDD is
about 4W. [1][2]

Now considering the environments we're gonna head into we're looking at
typically 1-3 days of power backup for the server (lets average out at 2).

That means, the battery backup needed is:
4 * 24 * 2 = 192 W-hr

*That comes out to roughly $25-35 in battery costs* (again based on quick
google searches for battery costs). *If you want a longer life from you're
battery, you're looking at about $50-60 in battery costs.*

Now if we're also giving solar backup, based on the calculator here
[3] we're going to need about a 25-30W solar panel (for just those 4 extra
watts). Again, google tells me that *such panels retail for about $65-80.*
*So, on average we'll save $100-$130 on TCO (total cost of ownership), if
we intend to provide an SSD as opposed to an HDD, considering the server
runs 24x7 and 2 days of backup is needed.*
On top of that, you're looking at less failures, a better operating
temperature range, and more durability.
Disclaimer: I don't claim to be an expert in this area (hence am cc'ing
Richard Smith), but this is what some back of the envelope number crunching
tells me.

[1] http://www.storagereview.com/ssd_vs_hdd
[3] http://www.batterystuff.com/kb/tools/solar-calculator.html,


On Fri, Aug 16, 2013 at 4:55 PM, James Cameron <quozl at laptop.org> wrote:

> On Fri, Aug 16, 2013 at 12:18:40PM -0500, David Farning wrote:
> > However the cost of a SSD is significantly higher than a normal
> > drive.
> What's the incremental cost of solar capture and storage for powering
> a hard drive compared to an SSD?
> --
> James Cameron
> http://quozl.linux.org.au/
> _______________________________________________
> Server-devel mailing list
> Server-devel at lists.laptop.org
> http://lists.laptop.org/listinfo/server-devel

Anish | anish at sugarlabs.org
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