Solved issue on red hat 5 error: fork: Resource temporarily unavailable
Just had an issue and solved it on red hat 5 getting error: fork: Resource temporarily unavailable
Research we did found this:
1. cron run scripts do not fully logon as the user. So if ulimit commands are issued in /etc/profile they will not get run when cron scripts run.
2. In dealing with user oracle on a machine with many databases, we found the ulimit -u to cause the issue. We had 800 oracle processes running (shows with ps -ef|grep oracle|wc -l), but a bash shell would work ok with ulimit -u 2020 but would fail with ulimit -u 2010.
Turns out process limits must be a misnomer. Must include threads also. This command shows a number closer to our experience of what ulimit -u needed: ps -eLf|grep oracle|egrep -v root|wc -l
So the bottom line is, make sure your ulimit -u is set high enough when dealing with workloads such as oracle.