[ale] A little math

[Scott Castaline]

On 02/10/2010 12:14 PM, Sean McNealy wrote:
> Testing to a file on my machine (no raid going on)
> 512000000 bytes (512 MB) copied, 81.1661 s, 6.3 MB/s
>
> extrapolation: 1TB @ 6.3 MB/s is 44 hours.  Wow, that is a long time.
>
> I forget the relevant specs for this machine, but for comparison
> copying that same 512MB file was:
> 512000000 bytes (512 MB) copied, 7.091 s, 72.2 MB/s
>
> And... now I'm out of entropy!
>
> -Sean
>
> On Wed, Feb 10, 2010 at 11:35 AM, Scott Castaline<skotchman at gmail.com>  wrote:
>> Okay I've got a dumb question for you math types. How long should it
>> take to fill a 1TB hdd with random data using
>> "dd if=/dev/urandom of=/dev/sd"? I've done some more searching and found
>> some numbers and if I figured them right I'm looking at about 8 days. Is
>> this accurate?
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But don't you have to figure in creating the random data? This would 
affect the throughput to the hdd, wouldn't it? My system has AMD dual 
core ~ 2.6GHz with 4GB 800MHz RAM, so my time would be a little faster 
than someone with a single core say 2.0GHz and 2GB RAM. I'm not sure how 
much of an impact.

Anyway, I'm trying to figure out if I should just let it run its course 
or kill it now. Originally I had created the LVM stuff and did a ext4 
format with badblock -c -c which does a destructive write and read of 4 
data patterns which took ~ 23Hrs, so I may have foolishly thought that 
it would take less time to do this. Now I'm finding that thought was way 
out in left field. If I choose to terminate will that hurt anything or 
just leave a partially filled drive with random data?