SEMMSL = 250 (or max processes per instance) SEMMNS = 32000 (or higher) SEMOPM = 100 SEMMNI = 256 (or 1024 for large systems) Set persistently:
SHOW PARAMETER processes SHOW PARAMETER sessions Increase (e.g., to 2000): SEMMSL = 250 (or max processes per instance)
set semsys:seminfo_semmns=4096 set semsys:seminfo_semmni=1024 set semsys:seminfo_semmsl=512 (if instance is down): /etc/sysctl.conf sysctl -p :
vi /etc/security/limits.conf Add:
# Current semaphore limits (SEMMSL, SEMMNS, SEMOPM, SEMMNI) ipcs -ls | grep "max number of arrays" cat /proc/sys/kernel/sem Recommended for Oracle: SEMMSL = 250 (or max processes per instance)
ls -l $ORACLE_HOME/bin/oracle # Should have setuid (rwsr-s--x) chmod 6751 $ORACLE_HOME/bin/oracle Increase (Linux):
# shmmax = 80% of RAM, shmall = shmmax / 4096 (page size) echo "kernel.shmmax = 68719476736" >> /etc/sysctl.conf # 64GB echo "kernel.shmall = 16777216" >> /etc/sysctl.conf sysctl -p :