1、AMM转换ASMM
1）查看当前memory_target，memory_max_target参数值
SQL> show parameter target

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
archive_lag_target                   integer     0
db_flashback_retention_target        integer     1440
fast_start_io_target                 integer     0
fast_start_mttr_target               integer     0
memory_max_target                    big integer 728M
memory_target                        big integer 728M
parallel_servers_target              integer     16
pga_aggregate_target                 big integer 0
sga_target                           big integer 0

2）创建文本参数文件pfile
SQL> create pfile='/home/oracle/orcl.ora' from spfile;

File created.

3）把memory_target，memory_max_target从pfile删除
[oracle@oracle11g ~]$ vi orcl.ora
orcl.__db_cache_size=318767104
orcl.__java_pool_size=4194304
orcl.__large_pool_size=8388608
orcl.__oracle_base='/u01/app/oracle'#ORACLE_BASE set from environment
orcl.__pga_aggregate_target=306184192
orcl.__sga_target=457179136
orcl.__shared_io_pool_size=0
orcl.__shared_pool_size=117440512
orcl.__streams_pool_size=0
*.audit_file_dest='/u01/app/oracle/admin/orcl/adump'
*.audit_trail='db'
*.compatible='11.2.0.4.0'
*.control_files='/u01/app/oracle/oradata/orcl/control01.ctl','/u01/app/oracle/fast_recovery_area/orcl/control02.ctl'
*.db_block_size=8192
*.db_domain=''
*.db_name='ORCL'#Reset to original value by RMAN
*.db_recovery_file_dest_size=4385144832
*.db_recovery_file_dest='/home/oracle/archivelog'
*.diagnostic_dest='/u01/app/oracle'
*.dispatchers='(PROTOCOL=TCP) (SERVICE=orclXDB)'
*.open_cursors=300
*.processes=150
*.remote_login_passwordfile='EXCLUSIVE'
*.undo_tablespace='UNDOTBS1'

4）关闭当前数据库，使用修改后的pfile创建spfile，并且用spfile启动数据库
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> create spfile from pfile='/home/oracle/orcl.ora';

File created.

SQL> startup
ORACLE instance started.

Total System Global Area  221331456 bytes
Fixed Size                  2251856 bytes
Variable Size             163578800 bytes
Database Buffers           50331648 bytes
Redo Buffers                5169152 bytes
Database mounted.
Database opened.
SQL> show parameter target

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
archive_lag_target                   integer     0
db_flashback_retention_target        integer     1440
fast_start_io_target                 integer     0
fast_start_mttr_target               integer     0
memory_max_target                    big integer 0
memory_target                        big integer 0
parallel_servers_target              integer     4
pga_aggregate_target                 big integer 10M
sga_target                           big integer 0

5）修改sga_target，sga_max_size，pga_aggregate_target参数
SQL> alter system set sga_target=580m scope=spfile;

System altered.

SQL> alter system set sga_max_size=580m scope=spfile;

System altered.

SQL> alter system set pga_aggregate_target=116m scope=spfile;

System altered.

6）重启数据库使参数生效
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.

Total System Global Area  605450240 bytes
Fixed Size                  2255632 bytes
Variable Size             230687984 bytes
Database Buffers          369098752 bytes
Redo Buffers                3407872 bytes
Database mounted.
Database opened.
SQL> show parameter target

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
archive_lag_target                   integer     0
db_flashback_retention_target        integer     1440
fast_start_io_target                 integer     0
fast_start_mttr_target               integer     0
memory_max_target                    big integer 0
memory_target                        big integer 0
parallel_servers_target              integer     16
pga_aggregate_target                 big integer 116M
sga_target                           big integer 580M
SQL>
SQL> show parameter sga

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
lock_sga                             boolean     FALSE
pre_page_sga                         boolean     FALSE
sga_max_size                         big integer 580M
sga_target                           big integer 580M
SQL> show parameter pga

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
pga_aggregate_target                 big integer 116M

2、查看系统当前的大页使用情况
[oracle@oracle11g ~]$ grep -i hugepages /proc/meminfo
AnonHugePages:     20480 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB

注：可以看到此时未开启大页

3、查看当前数据库sga_max_size参数值
SQL> show parameter sga_max_size

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
sga_max_size                         big integer 580M

4、运行hugepages_settings.sh脚本设置大页数
[oracle@oracle11g ~]$ vi hugepages_settings.sh
[oracle@oracle11g ~]$ chmod +x hugepages_settings.sh
[oracle@oracle11g ~]$
[oracle@oracle11g ~]$ ll hugepages_settings.sh
-rwxr-xr-x 1 oracle oinstall 3266 Jul 15 16:34 hugepages_settings.sh
[oracle@oracle11g ~]$ cat hugepages_settings.sh
#!/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

[oracle@oracle11g ~]$ sh hugepages_settings.sh

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...

Recommended setting: vm.nr_hugepages = 294

oracle建议配置大页数量为294.

5.在内核配置文件sysctl.conf增加一行
vm.nr_hugepages = 294

多次执行sysctl -p使参数生效

[root@oracle11g ~]# sysctl -p
net.ipv4.ip_forward = 0
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.default.accept_source_route = 0
kernel.sysrq = 0
kernel.core_uses_pid = 1
net.ipv4.tcp_syncookies = 1
kernel.msgmnb = 65536
kernel.msgmax = 65536
fs.aio-max-nr = 1048576
fs.file-max = 6815744
kernel.shmall = 2097152
kernel.shmmax = 2147483648
kernel.shmmni = 4096
kernel.sem = 250 32000 100 128
net.ipv4.ip_local_port_range = 9000 65500
net.core.rmem_default = 262144
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 1048576
net.ipv4.tcp_wmem = 262144 262144 262144
net.ipv4.tcp_rmem = 4194304 4194304 4194304
vm.nr_hugepages = 294
[root@oracle11g ~]#
[root@oracle11g ~]#
[root@oracle11g ~]# grep -i huge /proc/meminfo
AnonHugePages:     20480 kB
HugePages_Total:     294
HugePages_Free:      294
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB

如果HugePages_Free未达到设定的值，多次执行sysctl -p直到导到设定的值为止。

6、设置内存锁
[root@oracle11g ~]# vi /etc/security/limits.conf
oracle           soft    memlock unlimited
oracle           hard    memlock unlimited

7、重启数据库查看大页使用情况
重启数据库过程中不断执行grep -i huge /proc/meminfo，能看到HugePages_Free:的数量不断减少，说明大页正在被使用。
[root@oracle11g ~]# grep -i huge /proc/meminfo
AnonHugePages:     18432 kB
HugePages_Total:     294
HugePages_Free:      293
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB

参考连接：
https://www.modb.pro/db/77455