This morning the / file system was full on one of our AIX servers:

root@host[/root] > df
Filesystem 512-blocks Free %Used Iused %Iused Mounted on
/dev/hd4 524288 0 100% 5311 89% /


I didn’t take more than a few seconds to realize where this came from:


root@host[/root] > cd /
root@host[/] > du -x -k | sort -n | tail -5
14348 ./etc/perf
15328 ./lpp/bos
30900 ./etc
180880 ./dev
258580 .
root@host[/] > cd dev
root@nim1[/dev] > ls -lSr | tail -1
-rw-r--r-- 1 root system 185118720 Sep 2 15:26 null 2>&1


Interesting redirection…