>Check "pgrep -u mahmood | wc -l" - if it reports number close to or above >1000 (default limit 1024), then it's that.
# pgrep -u mahmood | wc -l 2118 !! That's it I will change that. Meanwhile, what will happen to the those which are beyond the limit? Are they running? Regards, Mahmood On Thursday, October 24, 2013 2:26 AM, Vladimir Mosgalin <mosga...@vm10124.spb.edu> wrote: Hi Mahmood Naderan! On 2013.10.23 at 15:15:16 -0700, Mahmood Naderan wrote next: > As root, I can not su to my user > > [root@tiger ~]# su - mahmood > su: cannot set user id: Resource temporarily unavailable > > > Which resource is unavailable right now? how can I find that? Maybe too many processes for that user? Check "pgrep -u mahmood | wc -l" - if it reports number close to or above 1000 (default limit 1024), then it's that. You can check limits for current user with "ulimit -a" and tweak them in /etc/security/limits.conf and /etc/security/limits.d/* (1024 processes per user is set in /etc/security/limits.d/90-nproc.conf) There are also other limits you can exceed, like limits on open files, or it can be limitation of selinux policies and few other causes - but error in setuid() is likely process limit. If it's something else, you should run "su" under strace ("strace -f" would be useful) and examine its output. You can solve (nearly) all mysteries like this with strace. -- Vladimir