using dd to zero out a HDD prior to returning it to Seagate...

graysky · 2009-04-08 20:49:03

Basically, I have a 750 HDD that is getting RMA'ed to Seagate, but I wanna wipe it clean of my files. I'm doing the following:

# dd if=/dev/zero of=/dev/sdd1

This is my first time using dd and I'm noticing that it doesn't give my any feedback as to progress, time remaining etc. Do you guys have any thoughts as to the time it should take to wipe out the entire partition?

Odysseus · 2009-04-08 20:53:16

Estimating a conservative 50 MB/s write speed... 4 hours or so.

And you might want to aim that dd at /dev/sdd (the entire drive) not just /dev/sdd1 (the first partition).

Last edited by Odysseus (2009-04-08 20:55:14)

graysky · 2009-04-08 20:56:19

Thanks for the reply... I thought /dev/sdd would be the MBR on /dev/sdd? Luckily, it only has one enormous partition

Nicolae · 2009-04-08 21:01:26

kill -USR1 `pidof dd` should make it print progress to screen.

graysky · 2009-04-08 21:07:38

Nicolae wrote:

kill -USR1 `pidof dd` should make it print progress to screen.

Hmm... I should execute this from a second shell as root? I executed the above command in its own shell and it has been running for a good 1/2 hour now...

Last edited by graysky (2009-04-08 21:08:54)

Odysseus · 2009-04-08 21:10:35

nvm

Last edited by Odysseus (2009-04-08 21:11:00)

Procyon · 2009-04-08 21:13:58

Also consider DBAN.

graysky · 2009-04-08 21:25:27

Odysseus wrote:

nvm

??

Nicolae · 2009-04-08 21:38:42

graysky wrote:

Nicolae wrote:
kill -USR1 `pidof dd` should make it print progress to screen.
Hmm... I should execute this from a second shell as root? I executed the above command in its own shell and it has been running for a good 1/2 hour now...

Yeah, just run it in another shell.

graysky · 2009-04-08 22:17:20

# kill -USR1 6806

Gave the following in the original shell:

dd if=/dev/zero of=/dev/sdd1
112734781+0 records in
112734781+0 records out
57720207872 bytes (58 GB) copied, 6175.38 s, 9.3 MB/s

Amazing... so in 1.3 hours it only did 58 GB? Doesn't that seem kinda slow for a modern 7200 SATAII drive?

fukawi2 · 2009-04-08 23:02:47

graysky wrote:

Amazing... so in 1.3 hours it only did 58 GB? Doesn't that seem kinda slow for a modern 7200 SATAII drive?

You can try increasing the size of blocks it writes with:

dd if=/dev/zero of=/dev/sdd1 bs=4294967296

4mb blocks. I find this works much quicker.

Last edited by fukawi2 (2009-04-08 23:03:02)

dotbmj · 2009-04-08 23:16:14

graysky wrote:

# kill -USR1 6806
Gave the following in the original shell:
dd if=/dev/zero of=/dev/sdd1
112734781+0 records in
112734781+0 records out
57720207872 bytes (58 GB) copied, 6175.38 s, 9.3 MB/s
Amazing... so in 1.3 hours it only did 58 GB? Doesn't that seem kinda slow for a modern 7200 SATAII drive?

If you don't specify a byte size the dd command will default to something very unreasonable like 1 byte, though I forget exactly what it defaults to. The point is, you need to specify the bs parameter.

e.g.:
dd if=/dev/zero of=/dev/sdd bs=1M

Would copy 1MiB chunks until it can't write any more, and even if the last chunk is less than 1MiB, it'll still write through it and then stop with an error saying the disk is full (obviously)

Last edited by dotbmj (2009-04-08 23:17:15)

graysky · 2009-04-08 23:25:53

ahhh.... much better. bs=1M gave 110 MB/s as did the bs=4M ...wish I knew that 2 h ago

Can someone explain to me how the kill -USR1 command works exactly?

Jack B · 2009-04-09 00:26:55

kill is used to send signals to programs. One common signal you'll see is number 9, KILL, which forces a program to quit. There are a whole load of predefined ones (KILL, TERM, HUP...), which have specific meaning, and some others which vary from program to program. USR1 is one of theese, and dd interprets it as an instruction to print it's progress.

Last edited by Jack B (2009-04-09 00:35:51)

graysky · 2009-04-09 06:57:26

Cool, learned something new today. BTW, it took just shy of 3 h to finish the entire 750 GB.

$ sudo dd if=/dev/zero of=/dev/sdd1 bs=1M
22697+0 records in
22697+0 records out
23799529472 bytes (24 GB) copied, 249.917 s, 95.2 MB/s
44978+0 records in
44978+0 records out
47162851328 bytes (47 GB) copied, 484.785 s, 97.3 MB/s
160223+0 records in
160223+0 records out
168005992448 bytes (168 GB) copied, 2102.25 s, 79.9 MB/s
209635+0 records in
209635+0 records out
219818229760 bytes (220 GB) copied, 2868.86 s, 76.6 MB/s
dd: writing `/dev/sdd1': No space left on device
715403+0 records in
715402+0 records out
750153729024 bytes (750 GB) copied, 10718 s, 70.0 MB/s

Arch Linux

#1 2009-04-08 20:49:03

using dd to zero out a HDD prior to returning it to Seagate...

#2 2009-04-08 20:53:16

Re: using dd to zero out a HDD prior to returning it to Seagate...

#3 2009-04-08 20:56:19

Re: using dd to zero out a HDD prior to returning it to Seagate...

#4 2009-04-08 21:01:26

Re: using dd to zero out a HDD prior to returning it to Seagate...

#5 2009-04-08 21:07:38

Re: using dd to zero out a HDD prior to returning it to Seagate...

#6 2009-04-08 21:10:35

Re: using dd to zero out a HDD prior to returning it to Seagate...

#7 2009-04-08 21:13:58

Re: using dd to zero out a HDD prior to returning it to Seagate...

#8 2009-04-08 21:25:27

Re: using dd to zero out a HDD prior to returning it to Seagate...

#9 2009-04-08 21:38:42

Re: using dd to zero out a HDD prior to returning it to Seagate...

#10 2009-04-08 22:17:20

Re: using dd to zero out a HDD prior to returning it to Seagate...

#11 2009-04-08 23:02:47

Re: using dd to zero out a HDD prior to returning it to Seagate...

#12 2009-04-08 23:16:14

Re: using dd to zero out a HDD prior to returning it to Seagate...

#13 2009-04-08 23:25:53

Re: using dd to zero out a HDD prior to returning it to Seagate...

#14 2009-04-09 00:26:55

Re: using dd to zero out a HDD prior to returning it to Seagate...

#15 2009-04-09 06:57:26

Re: using dd to zero out a HDD prior to returning it to Seagate...

Board footer