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January 12, 2021 22:30
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#!/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 Oracle Support | |
# http://support.oracle.com | |
# Welcome text | |
echo " | |
This script is provided by Doc ID 401749.1 from My Oracle Support | |
(http://support.oracle.com) where it is intended to compute values for | |
the recommended HugePages/HugeTLB configuration for the current shared | |
memory segments on Oracle Linux. Before proceeding with the execution please note following: | |
* For ASM instance, it needs to configure ASMM instead of AMM. | |
* The 'pga_aggregate_target' is outside the SGA and | |
you should accommodate this while calculating the overall size. | |
* In case you changes the DB SGA size, | |
as the new SGA will not fit in the previous HugePages configuration, | |
it had better disable the whole HugePages, | |
start the DB with new SGA size and run the script again. | |
And make sure that: | |
* Oracle Database instance(s) are up and running | |
* Oracle Database 11g Automatic Memory Management (AMM) is not setup | |
(See Doc ID 749851.1) | |
* The shared memory segments can be listed by command: | |
# ipcs -m | |
Press Enter to proceed..." | |
read | |
# 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 $KERN in | |
'2.4') HUGETLB_POOL=`echo "$NUM_PG*$HPG_SZ/1024" | bc -q`; | |
echo "Recommended setting: vm.hugetlb_pool = $HUGETLB_POOL" ;; | |
'2.6') echo "Recommended setting: vm.nr_hugepages = $NUM_PG" ;; | |
'3.8') echo "Recommended setting: vm.nr_hugepages = $NUM_PG" ;; | |
'3.10') echo "Recommended setting: vm.nr_hugepages = $NUM_PG" ;; | |
'4.1') echo "Recommended setting: vm.nr_hugepages = $NUM_PG" ;; | |
'4.14') echo "Recommended setting: vm.nr_hugepages = $NUM_PG" ;; | |
'4.18') echo "Recommended setting: vm.nr_hugepages = $NUM_PG" ;; | |
'5.4') echo "Recommended setting: vm.nr_hugepages = $NUM_PG" ;; | |
*) echo "Kernel version $KERN is not supported by this script (yet). Exiting." ;; | |
esac | |
# End |
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