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From Bryan Talbot <btal...@aeriagames.com>
Subject Re: cassandra vs. mongodb quick question(good additional info)
Date Wed, 20 Feb 2013 20:04:14 GMT
This calculation is incorrect btw.  10,000 GB transferred at 1.25 GB / sec
would complete in about 8,000 seconds which is just 2.2 hours and not 5.5
days.  The error is in the conversion (1hr/60secs) which is off by 2 orders
of magnitude since (1hr/3600secs) is the correct conversion.

-Bryan


On Mon, Feb 18, 2013 at 5:00 PM, Hiller, Dean <Dean.Hiller@nrel.gov> wrote:

> Google "10 gigabit in gigabytes" gives me 1.25 gigabytes/second  (yes I
> could have divided by 8 in my head but eh…course when I saw the number, I
> went duh)
>
> So trying to transfer 10 Terabytes  or 10,000 Gigabytes to a node that we
> are bringing online to replace a dead node would take approximately 5
> days???
>
> This means no one else is using the bandwidth too ;).  10,000Gigabytes * 1
> second/1.25 * 1hr/60secs * 1 day / 24 hrs = 5.555555 days.  This is more
> likely 11 days if we only use 50% of the network.
>
> So bringing a new node up to speed is more like 11 days once it is
> crashed.  I think this is the main reason the 1Terabyte exists to begin
> with, right?
>
>

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