I’ve been testing some new kernel tunings for Oracle databases the last few days, and experienced the odd error “error: unknown error 22 setting key ‘kernel.shmall’” when trying to sort out shared memory. Even more bizarre was the fact the setting was actually being set just fine.

After Googling a bit I couldn’t fathom out what this error meant or what was really wrong. So I did a quick strace on a ‘sysctl -p’. Bingo.

I had a comment at the end of the line in sysctl.conf! It was that simple. Move the comment to the line above, et voila, no whining!