zero deleted blocks
Olivier Smedts
olivier at gid0.org
Mon Aug 13 20:15:58 UTC 2012
2012/8/13 Steven Schlansker <stevenschlansker at gmail.com>:
>
> On Aug 13, 2012, at 2:27 AM, Olivier Smedts <olivier at gid0.org> wrote:
>> Did you try a classic "dd if=/dev/zero of=a-file-on-the-pool" ? This
>> won't give good results if you do this on a filesystem with
>> compression enabled.
>
> ZFS uses copy on write (http://en.wikipedia.org/wiki/ZFS#Copy-on-write_transactional_model) so overwriting with zeroes will actually allocate new space to hold all the zeroed data and leave the old data mostly untouched.
Only until all the free space is consumed !
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