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 Post subject: How long for erasing a 2 Terabyte HDD?
PostPosted: September 17th, 2010, 19:48 
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Joined: September 17th, 2010, 19:41
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How long will it take for a standard computer to fully erase (=low level format) a Two-Terabyte HDD?? Either using MHDD or HD Low-Level Format Tool... :?: :?: :?: :?: :?:

Thanks in advance!


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 Post subject: Re: How long for erasing a 2 Terabyte HDD?
PostPosted: September 17th, 2010, 23:05 
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Joined: September 8th, 2009, 18:21
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Location: Australia
Assuming an average data transfer rate of 100MB/s, it should take ...

(2 x 10^12) / (100 x 10^6) / 3600

= 5.6 hours

The manufacturer may also specify the time required for a full security erase. This will be reported in the 512-byte Identify Device data block.

For example, Seagate's ST32000542AS model specifies a value of 0xC4 for word 89:
http://www.users.on.net/~fzabkar/HDD/ST ... W0CJN5.TXT

This is equivalent to 196 minutes in decimal, ie 3 hours 16 minutes.


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 Post subject: Re: How long for erasing a 2 Terabyte HDD?
PostPosted: September 18th, 2010, 2:41 
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Joined: March 28th, 2008, 7:52
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Location: Europe, Hungary
2TB drives can perform 110-130MB/s in the beginning, and only 60-70MB/s in the end!


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 Post subject: Re: How long for erasing a 2 Terabyte HDD?
PostPosted: September 18th, 2010, 3:16 
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N.C. wrote:
2TB drives can perform 110-130MB/s in the beginning, and only 60-70MB/s in the end!

That depends on the RPM and the data density. In any case I assumed an average value of 100 MB/s which is reasonable in light of the following examples.

This ST32000641AS appears to be a 7200 RPM, 600GB / platter drive:
http://images.anandtech.com/reviews/mot ... neRcoS.jpg

Its average transfer rate is 110 MB/s, and maximum is 142 MB/s.

When I say 600GB per platter, I mean that the bits per track is equivalent to a 600GB per platter drive rather than the actual capacity of 500 GB per platter.

ST32000542AS 5900 RPM, 600GB per platter drive, 119 MB/s max, 94 MB/s avg:
http://blogimg.goo.ne.jp/user_image/3f/ ... 665f22.jpg
http://users.telenet.be/Mastakilla/HDs/ ... write2.JPG
http://hardware.mydrivers.com/img/20090806/01270267.jpg

HD203WI, 5400 RPM, 115MB/s max:
http://i48.tinypic.com/b7x47a.jpg


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 Post subject: Re: How long for erasing a 2 Terabyte HDD?
PostPosted: September 18th, 2010, 6:41 
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Joined: September 17th, 2010, 19:41
Posts: 2
Location: spain
fzabkar wrote:
Assuming an average data transfer rate of 100MB/s, it should take ...

(2 x 10^12) / (100 x 10^6) / 3600

= 5.6 hours

The manufacturer may also specify the time required for a full security erase. This will be reported in the 512-byte Identify Device data block.

For example, Seagate's ST32000542AS model specifies a value of 0xC4 for word 89:
http://www.users.on.net/~fzabkar/HDD/ST ... W0CJN5.TXT

This is equivalent to 196 minutes in decimal, ie 3 hours 16 minutes.


Thankyou!! :D :D :D :D

Does it make sense to perform a low-level-format in order to "reset" SMART "Reallocated Sectors Count Attrribute" back to "as new hdd" value? I've heard different opinions on this...


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 Post subject: Re: How long for erasing a 2 Terabyte HDD?
PostPosted: September 18th, 2010, 22:10 
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jotavalla wrote:
Does it make sense to perform a low-level-format in order to "reset" SMART "Reallocated Sectors Count Attrribute" back to "as new hdd" value?

Your "low level format" utility merely zero-fills the user accessible sectors. The SMART Reallocated Sectors Count will not be reset. In fact, if there are marginal sectors showing under the Current Pending Sectors attribute, then these will be retested transparently by the drive. If they pass, they will be returned to service, otherwise they will be replaced with spares, in which case the Reallocated Sectors Count will actually increase.


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 Post subject: Re: How long for erasing a 2 Terabyte HDD?
PostPosted: September 19th, 2010, 6:01 
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Joined: March 28th, 2008, 7:52
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Location: Europe, Hungary
fzabkar wrote:
jotavalla wrote:
Does it make sense to perform a low-level-format in order to "reset" SMART "Reallocated Sectors Count Attrribute" back to "as new hdd" value?

Your "low level format" utility merely zero-fills the user accessible sectors. The SMART Reallocated Sectors Count will not be reset. In fact, if there are marginal sectors showing under the Current Pending Sectors attribute, then these will be retested transparently by the drive. If they pass, they will be returned to service, otherwise they will be replaced with spares, in which case the Reallocated Sectors Count will actually increase.


Agree, it is correct.


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