Zeroing out ununsed space in a ext3 partition

saravkrish · 11-19-2004, 04:03 AM

Hi,

How do I zero out the usused space of an ext3 partition without loosing any data. I need to do this to make sure that the disk imaging software is not accidentally imaging old data in the unused blocks.

Thanks,
Sarav

jailbait · 11-19-2004, 02:54 PM

"How do I zero out the usused space of an ext3 partition without loosing any data. I need to do this to make sure that the disk imaging software is not accidentally imaging old data in the unused blocks."

You can set free space to zeros when you delete files by deleting with the shred command and the -z option. See man shred.

For existing free space you could allocate a temporary file that uses up all of the free space and then shred the temporary file.

-------------------------
Steve Stites

saravkrish · 11-19-2004, 03:10 PM

Hi,

Checked out "man shred" - it doesn't work for journaling filesystems. I anyway wanted to clear only the existing free space and did this to take care of that-

cat /dev/urandom > dump
rm dump
cat /dev/zero > dump
rm dump

Note: Your working directory should be in the parition that you want to wipe the free space.

Thanks,
Sarav