Blog O’ Matty

Ridding your Solaris host of zombie processes

We encountered a nasty bug in our backup software this week. When this bug is triggered, each job (one process is created per job) that completes will turn into a zombie. After a few days we will have hundreds or even thousands of zombie processes, which if left unchecked will eventually lead to the system-side process table filling up. Solaris comes with a nifty tool to help deal with zombies (no, they don’t ship you a shotgun with your media kit), and it comes by the name preap. To use preap, you can pass it the PID of the zombie process you want to reap:

$ ps -ef | grep defunct

    root   646   426   0        - ?           0:00 <defunct>
    root  1489 12335   0 09:32:54 pts/1       0:00 grep defunct

$ preap 646
646: exited with status 0

This will cause the process to exit, and the kernel can then free up the resources that were allocated by that process. On a related note, if you haven’t seen the movie zombieland you are missing out!!!! That movie is hilarious!