linux hugepage + oracle 11.2.0.4详解程序员

1. 

OS  

        linux : Oracle Linux Server release 6.8

        memory: 64G

DB  

          version: 11.2.0.4



linux hugepage 与 AMM 不兼容,所以要退化到 ASMM

SGA,PGA设置为最保守参数

alter system set sga_max_size=28G scope=spfile;

alter system set sga_target=28G scope=spfile;

alter system set pga_aggregate_target=10G scope=spfile;

alter system set memory_max_target=0 scope=spfile;

alter system set memory_target=0 scope=spfile;

alter system reset memory_max_target;

alter system reset memory_target;

create pfile from spfile;

shutdown immediate;

vi pfile 屏蔽 memory_max_target，memory_target 参数,禁用AMM

启动实例

startup pfile= ‘/u01/app/oracle/product/11.2.0/db_1/dbs/initfsdb1.ora’;

2.在/etc/security/limits.conf 添加如下行

oracle           soft     memlock    54712408

oracle           hard    memlock    54712408

注意，这里设置的值均以kb为单位的！

设置用户内存配置，有个计算规则是：实际物理内存 > 锁定内存 >=HugePages_Total*Hugepagesize；这个要简单比较下

修改/etc/security/limits.conf参数文件，添加数据库实例用户的memlock限制，

建议限制的值free -t 的total值小点,也可以设置为数据库服务器物理内存大小

3.nr_hugepages的计算公式:nr_hugepages>=sga(mb)/Hugepagesize(mb)

运行oracle 的 hugepage 脚本，给出建议值 vm.nr_hugepages=XXXX

[[email protected] ~]$ pwd

/home/oracle

[[email protected] ~]$ ./hugepages_settings.sh

Oracle Linux: Shell Script to Calculate Values Recommended Linux HugePages / HugeTLB Configuration (文档 ID 401749.1)

hugepages_settings.sh 脚本内容如下

#!/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 SGA 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

    ‘2.2’) echo “Kernel version $KERN is not supported. Exiting.” ;;

    ‘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” ;;

esac

# End

4.停止Oracle DB

5.同步数据

#sync

#echo 3 > /proc/sys/vm/drop_cache

vi /etc/sysctl.conf 

#vm.min_free_kbytes=524288

vm.nr_hugepages=XXXXX 

修改 /etc/fstab 

调整 /dev/shm 为默认

大页的大小要稍微大于SGA

如果有条件重启下OS，如果没有条件执行 sysctl -p

禁止linux 的透明大页

#vi /etc/rc.local 

echo ‘never’ > /sys/kernel/mm/transparent_hugepage/enabled 

echo ‘never’ > /sys/kernel/mm/transparent_hugepage/defrag

reboot

6.查看是否启用大页

# cat /proc/meminfo |grep -i huge
AnonHugePages:         0 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB

7.启动数据库