how long to zero a drive with dd? [closed]
It depends on many factors, including but not limited to:
- Disk speed (RPM)
- Disk built-in cache
- Number of platters and whether it can write to multiple platters simultaneously
- Disk interface (SATA/SCSI, etc)
- Interface controller performance
- Configuration of the drives (eg. separate channels or same channel)
Additionally, although zeroing a drive is a simple task for the CPU and RAM, there may still be an effect from:
- CPU performance
- Available RAM
- Speed of RAM
- Other tasks being done at the same time
- Power management settings
Assuming a fairly recent computer with middle-grade drives, on a minimal linux boot disk running JUST the zeroing operation (no gui, internet, etc) loaded entirely to RAM, it could be anywhere from 2-12 hours. If I had to throw a single number out, I'd say closer to 3 and a half hours, but again, there's not enough information to get a good estimate other than actually doing it.
If you have more than 1GB free space, you could try mounting the drive and running dd if=/dev/zero bs=512 count=2048 of=/tmp/tempzero or some other file. If you know more about the optimal block size for fastest writing to your drive, you can use that for the bs value (in kilobytes) and set the count to whatever gets you the filesize you want. Then you can use that to get a better estimate without losing data. It will just create a large file that contains zeros.
With a partition of +100 GB, Acer Aspire 5750G, external sata hdd, usb 2, 5400rpm:
xxxx@acer-ubuntu:~$ sudo dd if=/dev/zero of=/dev/sdb2 bs=8M
[sudo] password for xxxx:
dd: writing `/dev/sdb2': No space left on device
12500+0 records in
12499+0 records out
104856551424 bytes (105 GB) copied, 2846.87 s, 36.8 MB/s
and
xxxx@acer-ubuntu:~$ sudo dd if=/dev/zero of=/dev/sdb1 bs=8M
[sudo] password for xxxx:
dd: writing `/dev/sdb1': No space left on device
6579+0 records in
6578+0 records out
55183409152 bytes (55 GB) copied, 1497.23 s, 36.9 MB/s