The HugePage calculation requires SGA to take effect, and the memory needs to be configured first
#! /bin/bash # # hugepages_settings.sh # # Linux bash script to compute values for the # recommended HugePages/HugeTLB configuration # on Oracle Linux # # Note: This script does calculation for all shared memory # segments available when the script is run, No matter it # is an Oracle RDBMS shared memory segment or not. # # This script is provided by Doc ID 401749.1 from My server Oracle Support # http://support.oracle.com # Check for the kernel version KERN=`uname -r | awk -F. '{ printf("%d.%d\n",$1,$2); }'` # Find out the HugePage size HPG_SZ=`grep Hugepagesize /proc/meminfo | awk '{print $2}'` if [ -z "$HPG_SZ" ]; then echo "The hugepages may not be supported in the system where the script is being executed." exit 1 fi # Initialize the counter NUM_PG=0 # Cumulative number of pages required to handle the running shared memory segments for SEG_BYTES in `ipcs -m | cut -c44-300 | awk '{print $1}' | grep "[0-9][0-9]*"` do MIN_PG=`echo "$SEG_BYTES/($HPG_SZ*1024)" | bc -q` if [ $MIN_PG -gt 0 ]; then NUM_PG=`echo "$NUM_PG+$MIN_PG+1" | bc -q` fi done RES_BYTES=`echo "$NUM_PG * $HPG_SZ * 1024" | bc -q` # An SGA less than 100MB does not make sense # Bail out if that is the case if [ $RES_BYTES -lt 100000000 ]; then echo "***********" echo "** ERROR **" echo "***********" echo "Sorry! There are not enough total of shared memory segments allocated for HugePages configuration. HugePages can only be used for shared memory segments that you can list by command: # ipcs -m of a size that can match an Oracle Database SGA. Please make sure that: * Oracle Database instance is up and running * Oracle Database 11g Automatic Memory Management (AMM) is not configured" Exit 1 fi # Finish with results case $KERN in '2.4') HUGETLB_POOL = ` echo "$$HPG_SZ NUM_PG * / 1024" | BC - q `; echo "vm.hugetlb_pool = $HUGETLB_POOL" ;; '2.6' | '3.8' | '3.10' | '4.1' | '4.14' | '4.18' | '5.4') echo "vm. Nr_hugepages = $NUM_PG";; *) echo "Kernel version $KERN is not supported by this script (yet). Exiting." ;; esac # End