一、环境描述
系统：rhel 7.3
数据库：Oracle 12.2.0.1

二、使用AMM

$export ORACLE_SID=orcl
$sqlplus / as sysdba

SQL*Plus: Release 12.2.0.1.0 Production on Thu Aug 16 11:17:25 2018

Copyright (c) 1982, 2016, Oracle. All rights reserved.

Connected to:
Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production

SQL> show parameter target

NAME TYPE VALUE

archive_lag_target integer 0
db_big_table_cache_percent_target string 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 782M
sga_target big integer 2352M
target_pdbs integer 0

SQL>
SQL> alter system set memory_target=5g scope=spfile;

System altered.

SQL> startup force;
ORA-00845: MEMORY_TARGET not supported on this system
SQL> exit
Disconnected from Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production
$df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/rhel-root 30G 28G 1.5G 96% /
devtmpfs 3.9G 0 3.9G 0% /dev
tmpfs 3.9G 84K 3.9G 1% /dev/shm
tmpfs 3.9G 8.8M 3.9G 1% /run
tmpfs 3.9G 0 3.9G 0% /sys/fs/cgroup
/dev/mapper/vgdata-lvdata01 8.0G 33M 8.0G 1% /oracle
/dev/sda1 197M 150M 48M 77% /boot
tmpfs 783M 16K 783M 1% /run/user/42
tmpfs 783M 0 783M 0% /run/user/0
$exit
logout
[root@roidb01 ~]#
[root@roidb01 ~]#
[root@roidb01 ~]# vi /etc/fstab
[root@roidb01 ~]#more /etc/fstab
/dev/mapper/rhel-root / xfs defaults 0 0
UUID=e991f183-78ab-43cf-ba5a-2c0598867972 /boot xfs defaults 0 0
/dev/mapper/rhel-swap swap swap defaults 0 0
/dev/vgdata/lvdata01 /oracle xfs defaults 0 0
tmpfs /dev/shm tmpfs defaults,size=6G 0 0 ##添加一行

[root@roidb01 ~]# mount -o remount /dev/shm
[root@roidb01 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/rhel-root 30G 28G 1.5G 96% /
devtmpfs 3.9G 0 3.9G 0% /dev
tmpfs 6.0G 84K 6.0G 1% /dev/shm
tmpfs 3.9G 8.8M 3.9G 1% /run
tmpfs 3.9G 0 3.9G 0% /sys/fs/cgroup
/dev/mapper/vgdata-lvdata01 8.0G 33M 8.0G 1% /oracle
/dev/sda1 197M 150M 48M 77% /boot
tmpfs 783M 16K 783M 1% /run/user/42
tmpfs 783M 0 783M 0% /run/user/0
[root@roidb01 ~]# su - oracle
Last login: Thu Aug 16 08:34:52 CST 2018 on pts/0

$sqlplus / as sysdba

SQL*Plus: Release 12.2.0.1.0 Production on Thu Aug 16 12:19:20 2018

Copyright (c) 1982, 2016, Oracle. All rights reserved.

Connected to an idle instance.

SQL> exit
Disconnected
$export ORACLE_SID=orcl
$sqlplus / as sysdba

SQL*Plus: Release 12.2.0.1.0 Production on Thu Aug 16 12:19:39 2018

Copyright (c) 1982, 2016, Oracle. All rights reserved.

Connected to an idle instance.

SQL> startup
ORACLE instance started.

Total System Global Area 5368709120 bytes
Fixed Size 8632016 bytes
Variable Size 4211083568 bytes
Database Buffers 1140850688 bytes
Redo Buffers 8142848 bytes
Database mounted.
Database opened.
SQL> show parameter target;

NAME TYPE VALUE

archive_lag_target integer 0
db_big_table_cache_percent_target string 0
db_flashback_retention_target integer 1440
fast_start_io_target integer 0
fast_start_mttr_target integer 0
memory_max_target big integer 5G
memory_target big integer 5G
parallel_servers_target integer 16
pga_aggregate_target big integer 782M
sga_target big integer 2352M
target_pdbs integer 0
SQL> alter system set sga_target=0 scope=both;

System altered.

SQL> alter system set pga_aggregate_target=0 scope=both;

System altered.

SQL> show parameter target;

NAME TYPE VALUE

archive_lag_target integer 0
db_big_table_cache_percent_target string 0
db_flashback_retention_target integer 1440
fast_start_io_target integer 0
fast_start_mttr_target integer 0
memory_max_target big integer 5G
memory_target big integer 5G
parallel_servers_target integer 16
pga_aggregate_target big integer 0
sga_target big integer 0
target_pdbs integer 0
SQL>