Re: Wiping a disk partition

On 3 July 2025 22:20:31 BST, David Christensen <dpchrist@holgerdanske.com> wrote:
>On 6/25/25 03:16, Odhiambo Washington wrote:
>> root@gw:/home/wash # df -h
>> Filesystem     Size    Used   Avail Capacity  Mounted on
>> /dev/ada0p2    1.8T    552G    1.1T    33%    /
>> devfs          1.0K      0B    1.0K     0%    /dev
>> fdescfs        1.0K      0B    1.0K     0%    /dev/fd
>> procfs         8.0K      0B    8.0K     0%    /proc
>> linprocfs      8.0K      0B    8.0K     0%    /compat/linux/proc
>> linsysfs       8.0K      0B    8.0K     0%    /compat/linux/sys
>> /dev/ada1p2    1.8T    856G    802G    52%    /disk2
>
>
>On 7/3/25 02:24, Odhiambo Washington wrote:
>> What I did was:
>> 
>> umount /disk2
>> dd if=/dev/ada0 of=/dev/ada1 bs=1g status=progress
>
>
>If the computer was running in multi-user mode when you cloned ada0 to ada1, the root file system on ada0p2 will have been mounted read-write, any ada0 swap partition will have been active, and it is likely that foreground and/or background processes wrote to ada0 while cloning.  The last means the source and the clone are not the same, and the backup is incorrect.
>
>
>If you want to clone ada0 to ada1, then you must boot into single-user mode or boot live media; so that ada0 does not change while cloning. After making the clone, verify by using cmp(1) to do a byte-for-byte comparison of the source and the clone.


Or just copy the partition in question rather than the whole drive.

On multitasking system you can always put an & on the end of the rm command and let it run in the background. Probably the safest way to delete all the files if you're sure.