SCRIPT TÍNH TOÁN THAM SỐ HUGEPAGES

Script tính toán tham số hugepages

#!/bin/bash

#

# hugepages_settings.sh

#

echo "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" ;;

     *) echo "Unrecognized kernel version $KERN. Exiting." ;;

esac

# End

@ Trần Văn Bình - Founder of Oracle DBA AZ

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