ps showing duplicate process same PID
 

Hello. Hopefully someone can help. We have a few red hat 9 servers here running various common utilities eg sendmail, qpopper, apache, freeradius, bind etc.
One of these machines has started to behave strangely. This morning Bind just stopped working, nothing in the log to give a clue but it just would not resolve any names. ps -ef|grep named showed the process running twice under the same PID. Killed the PID and restarted the name server and all was well.

Just now we had radiusd just disappear from the process list. ps -ef|grep rad showed two instances of grep rad with the same PID again but did not show a running process of radius but looking at the logs on the machine people are still authenticating. The processes are not showing in /proc either but they are there as you can cd into them.

Any help to point us in the right direction will be greatly appreciated.

Thanks.