[Novalug] need dd help

[John Franklin]

Sounds a bit short.  100MB/s write speed would take 10,000 seconds to zero a 1TB drive.

jf

On Feb 13, 2012, at 12:36 AM, Jay Hart wrote:

> Not sure I understand what you are saying.  I should take a value such as 8
> seconds and multiply by a 1000?
> 
> So 8000 seconds should be over 2 hours and 10 minutes.  Sound about right to
> zero a 1TB drive?
> 
> Jay
> 
>> On Sun, Feb 12, 2012 at 10:37:22PM -0500, Jay Hart wrote:
>>> Jon,
>>> 
>>> So this will wipe my entire drive, 1k at a time.  1TB will take a while, I
>>> suspect.
>> 
>> Preview it by doing
>> 
>>  time dd if=/dev/zero of=junk bs=1k count=1048576
>> 
>> and multiple the time by 1000.  That should give an outer limit.
>> 
>> You could also try
>> 
>>  time dd if=/dev/zero of=junk bs=4k count=262144
>> 
>> and see if there is a speed-up.
>> 
>> Running the 1k command on three different systems I got 29,
>> 11, and 3 seconds.  Guess which one had the Solid State Drive :)
>> The 4k command ran about 20% faster.
>> 
>> Jon
>>> 
>>>> On Sun, Feb 12, 2012 at 10:17:04PM -0500, Jay Hart wrote:
>>>>> I think this command with totally wipe a drive:
>>>>> 
>>>>> dd if=/dev/zero of=/dev/devicename bs=1k
>>>>> 
>>>>> Yes/no. what exactly does the "bs=1k" do???
>>>> 
>>>> By default dd uses input and output buffers of 512 bytes.
>>>> These can be changed individually with ibs= and obs=.
>>>> Your option bs= changes both buffer sizes to 1024 bytes.
>>>> 
>>>> I find when making large transfers like this that a
>>>> larger buffer size greatly speeds up dd.  I'd suggest 4k.
>>>> 
>>>> jl
>>>> --
>>>> Jon H. LaBadie                  novalugml at jgcomp.com
>>>> 11226 South Shore Rd		(703) 787-0688 (H)
>>>> Reston, VA  20190		(609) 477-8330 (C)
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>>> 
>>> 
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>>>>> End of included message <<<
>> 
>> --
>> Jon H. LaBadie                  novalugml at jgcomp.com
>> 11226 South Shore Rd		(703) 787-0688 (H)
>> Reston, VA  20190		(609) 477-8330 (C)
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> 
> 
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-- 
John Franklin
franklin at elfie.org
ICBM: 39º 01' 58.4"N 77º 24' 49.6"W Z+84m