Is there any impact of reaping zombie processes? I will execute following command for reaping zombie /usr/bin/preap $(ps -ef | grep defunct | grep -v grep | awk '{ print $2 }' | xargs) Is there any service impact of this approach ?

If you reap a zombie before its parent, you lose whatever effect the reaping would have in the parent. This is obviously application-dependent.

There is very little reason to actively go and reap zombies. Some operating systems don't let you do it, short of manually ptracing the parent process and causing it to execute a `waitpid` system call. Solaris offers a `preap` utility, but the only case when you should use it is when a program is misbehaving and filling the process table with zombies.