doug at mail.sermon-archive.info
Mon Jul 10 00:34:08 UTC 2017
> On 9 July 2017, at 17:18, Valeri Galtsev <galtsev at kicp.uchicago.edu> wrote:
> On Sun, July 9, 2017 4:57 am, Doug Hardie wrote:
>> I have a FreeBSD 9.3 remote server that needs to be purged. I know that
>> rm -rf / will remove all the directory entries, but I need to write over
>> the drive. I thought that dd if=/dev/zero of=/dev/ada0 might do the
> If you were able to execute this, it still will not do the trick. What
> will happen is the following: the command at some point will descend into
> /dev and will delete block device / filesystem lives on, and after that
> point the command will just fail. I have vague recollection that that was
> one of the tricky questions on some sysadmin exam (Linux probably). I knew
> someone who actually did that on multi-user box he administered (space
> just snuck in after leading slash of absolute path). I happened to help
> him: we just mounted partitions on another machine and apart from /bin
> /boot and portion of /dev all still was there, so it was nothing like the
> disaster on can picture from nasty appearance of this command.
> Someone at some point mentioned that rm command goes into directories and
> subdirectories NOR in alphabetical order, so I left that out, but in
> incident I mention nothing but what alphabetically is before the device /
> filesystem lives on (/dev/hda2 was our case I believe) was lost.
> I hope, you had fun reading this ;-)
>> but it gives an not permitted error. The whole thing can crash and
>> burn at the end. This is an unmanned site so moving drives is not viable.
Thanks for the info. I've never tried the rm approach, but the dd approach seems to work. After a couple hours the machine became unresponsive and ssh sessions were terminated. I think the drive is now empty. I'd like to be able to get it back to verify, but that won't happen. I still have 3 more systems to do this to. The others will have to wait for awhile as I may still need them for a few more days.
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