On 4/15/23 10:14, Lorenzo Torres wrote:
Hello, I've run the dd command to wipe the data of an SD card:dd
if=/dev/zero of=/dev/rsdb1c bs=1MAfter quite some time it crashed
^^^^^^ bzzzt. game over.
saying that the / filesystem is full and even after a reboot the same
happens. Now I can't even run xorg because the fs is full. Any idea
on why this happened? I have a 1TB NVME SSD as root disk and I have
only a root partition as well as the efi partition on the root disk
^^^^^^^^^^^^^^^^^^^^^ game took a while to be over, didn't it?
As people have already said, you created a file, you didn't zero your
SD card.
But...what wasn't said (yet? as I'm typing this? Probably twenty
people will respond about this two seconds after I hit "SEND") was
pointing out this is one of many reasons NOT to create a huge root
partition and nothing else. Granted, OpenBSD has lots of
OpenBSD-only reasons, too, but one big root partition is Bad Unix
Administration.
If you had an appropriate sized root partition, perhaps 1G (default),
you would have quickly discovered something was wrong, probably in
a few seconds. Instead, it took a while, and you assumed you had
accomplished your mission of zeroing an SD card. So not only did
you fill root, your sensitive data is still on the card.
Many system administrators can tell you stories about thinking they
were backing up every night to tape, only to find out that they were
dumping a big backup *file* in their /dev directory rather than
putting their data to tape...and find this when they realize their
tape has never been written when they need a restore.
$DAYJOB involves helping maintain a bunch of systems that regularly
fill their root partitions. Not always by bad initial design,
but often because there was "plenty of space" on the root partition,
so someone started dropping data or applications there. And then,
one day...boom.
Partition your system. And / should be as small as you can sanely
get away with. That isn't to say it should be super-tiny. But
if you have 1GB to spare, it is probably too big. I did learn to
regret a 200MB root because OpenBSD grew a lot over around ten
years that I used that install.
Nick.
