OS
linux : Oracle Linux Server release 6.8
memory: 64G
DBversion: 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
[oracle@fsscdb ~]$ pwd
/home/oracle
[oracle@fsscdb ~]$ ./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 ",$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.localecho ‘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