My linux server "Number of processes created" and "Context switches" are growing incredibly fast
- by Jorge Fuentes González
I have a strange behaviour in my server :-/. Is a OpenVZ VPS (I think is OpenVZ, because /proc/user_beancounters exists and df -h returns /dev/simfs drive. Also ifconfig returns venet0). When I do cat /proc/stat, I can see how each second about 50-100 processes are created and happens about 800k-1200k context switches! All that info is with the server completely idle, no traffic nor programs running.
Top shows 0 load average and 100% idle CPU.
I've closed all non-needed services (httpd, mysqld, sendmail, nagios, named...) and the problem still happens. I do ps -ALf each second too and I don't see any changes, only a new ps process is created each time and the PID is just the same as before + 1, so new processes are not created, so I thought that process growing in cat /proc/stat must be threads (Yes, seems that processes in /proc/stat counts threads creation too as this states: http://webcache.googleusercontent.com/search?q=cache:8NLgzKEzHQQJ:www.linuxhowtos.org/System/procstat.htm&hl=es&tbo=d&gl=es&strip=1).
I've changed to /proc dir and done cat [PID]\status with all PIDs listed with ls (Including kernel ones) and in any process voluntary_ctxt_switches nor nonvoluntary_ctxt_switches are growing at the same speed as cat /proc/stat does (just a few tens/second), Threads keeps the same also.
I've done strace -p PID to all process too so I can see if any process is crating threads or something but the only process that has a bit of movement is ssh and that movement is read/write operations because of the data is sending to my terminal.
After that, I've done vmstat -s and saw that forks is growing at the same speed processes in /proc/stat does. As http://linux.die.net/man/2/fork says, each fork() creates a new PID but my server PID is not growing!
The last thing I can think of is that all process data that proc/stat and vmstat -s show is shared with all the other VPS stored in the same machine, but I don't know if that is correct... If someone can throw some light on this I would be really grateful.
