Re: SSD erase question

On and SSD if you have erased everything ssd “garbage collection” should help you if the drive it powered on.
But if you want to overwrite the drive
A simple overwrite with a text pattern with dc3dd.
dc3dd wipe=/dev/sdb tpat=nothingtoseehere
However if you are still worried that some controller optimization is interfering
with and actual memory location overwrite.  Go old school with dd and write
a file of random to the existing file system until it runs out of space.
dd if=/dev/urandon of=garbagetxtfile.txt




On Mar 21, 2022, at 7:14 AM, Damian Weber <dweber@htwsaar.de> wrote:


Hi all,

I'd like to have an answer on a secure FreeBSD way to erase 
SSDs before giving these away to someone for reusing it. 

Is the following enough to protect confidential data 
previously stored there?

1)  dd : overwriting with random bits (complete capacity)
2)  gpart create
3)  gpart add
4)  newfs

Details for an example with /dev/ada1 see below.

Thanks a lot,

  Damian


# fdisk ada1
******* Working on device /dev/ada1 *******
parameters extracted from in-core disklabel are:
cylinders=484521 heads=16 sectors/track=63 (1008 blks/cyl)

Figures below won't work with BIOS for partitions not in cyl 1
parameters to be used for BIOS calculations are:
cylinders=484521 heads=16 sectors/track=63 (1008 blks/cyl)

Media sector size is 512
Warning: BIOS sector numbering starts with sector 1
Information from DOS bootblock is:
The data for partition 1 is:
sysid 238 (0xee),(EFI GPT)
   start 1, size 488397167 (238475 Meg), flag 0
       beg: cyl 0/ head 0/ sector 2;
       end: cyl 1023/ head 255/ sector 63
The data for partition 2 is:
<UNUSED>
The data for partition 3 is:
<UNUSED>
The data for partition 4 is:
<UNUSED>

# gpart show ada1
=>       40  488397088  ada1  GPT  (233G)
        40       1024     1  freebsd-boot  (512K)
      1064  480246784     2  freebsd-ufs  [bootme]  (229G)
 480247848    8149280     3  freebsd-swap  (3.9G)

# dd if=/dev/random of=/dev/ada1 bs=512 count=488397088

# gpart create -s gpt ada1

# gpart add -t freebsd-ufs ada1

# newfs -U /dev/ada1p1