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Given

dd if=/dev/zero of=/dev/sda

provides sufficient wiping for our purposes, what is the fastest way to "zero" the drive? I have heard of this "Secure Erase" feature that is built in to hard drives but disabled by the bios. Will it be the fastest way or is there another?

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    one pass wipe like zero fill is the fastest, secure wipe just means more passes which is much longer process. No one has ever recovered data after a one pass overwrite, so in a sense this is as secure as it gets, more passes is just paranoia....nber.org/sys-admin/overwritten-data-guttman.html – Moab Nov 21 '11 at 16:37
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I assume, that hdparm's functionality does what you are referring to as "secure erase":

hdparm --security-erase NULL /dev/sdX

Never actually tried this (so no idea how it scales), tempted to do now though. Hopefully, someone more in the know will comment.

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Secure-Erase is a feature found mainly on SSD which may have this feature built into the controller.
On a magnetic disk many claim that if you just zero out a drive (e.g. with tools like dd), data may be recovered by the small magnetic differences between a previous zero and an overwritten one.
But if you overwrite with random data, then I think a single pass will be sufficient to prevent any decent data recovery.
That said the fastest way I found to write random data to a disk is as follows:

DEVICE=/dev/sdb
cryptsetup create cryptedDEV $DEVICE
# enter any passphrase, no need to remember it
DEVSIZE=$(cryptsetup status cryptedDEV | grep "size:.*sectors" | awk '{print $2*512}')
pv -s $DEVSIZE /dev/zero > /dev/mapper/cryptedDEV
cryptsetup remove cryptedDEV

The scheme is based on the idea of Eric Wheeler with the modification of Kruzi Krypr on linuxglobal.com
cryptsetup creates the random data from /dev/zero very fast.
pv copies the data to the whole disk showing the transfer rate.
I found that erasing a drive is as fast as the drive speed.
Im my case I could erase a USB3 disk with ~60MB/sec.

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