Oracle study之--“ORA-00845: MEMORY_TARGET not supported on this system"错误

系统环境：

操作系统：RedHat EL6(64)

Oracle： Oracle 11g R2

故障案例：

在Oracle 11gR2下调整内存参数：memory_target

SQL> show parameter mem

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
hi_shared_memory_address             integer     0
memory_max_target                    big integer 400M
memory_target                        big integer 400M
shared_memory_address                integer     0
SQL> alter system set memory_max_target=1200m scope=spfile;

System altered.

SQL> alter system set memory_target=1200m scope=spfile;

System altered.

SQL> show parameter sga

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
lock_sga                             boolean     FALSE
pre_page_sga                         boolean     FALSE
sga_max_size                         big integer 400M
sga_target                           big integer 0
SQL> show parameter shared

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
hi_shared_memory_address             integer     0
max_shared_servers                   integer
shared_memory_address                integer     0
shared_pool_reserved_size            big integer 6710886
shared_pool_size                     big integer 0
shared_server_sessions               integer
shared_servers                       integer     1
SQL> alter system set shared_pool_size=500m scope=spfile;

System altered.

SQL> show parameter java

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
java_jit_enabled                     boolean     TRUE
java_max_sessionspace_size           integer     0
java_pool_size                       big integer 0
java_soft_sessionspace_limit         integer     0
SQL> alter system set java_pool_size=300m scope=spfile;

System altered.

调整完成后，重新启动Instance：

SQL> startup force;
ORA-00845: MEMORY_TARGET not supported on this system
SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

查看linux系统文件系统：
[oracle@rh6 dbs]$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 18G 5.2G 12G 32% /
tmpfs 878M 72K 878M 1% /dev/shm
/dev/sda1 2.0G 62M 1.8G 4% /boot
/dev/sda3 12G 5.7G 5.4G 52% /u01
/dev/sda5 9.9G 4.9G 4.6G 52% /usr
/dev/sda7 4.2G 300M 3.7G 8% /var

---从以上可以看到，对于虚拟tmpfs的内存的文件系统，可用空间为878M，无法满足memory_target =1200M的内存需求

调整tmpfs：

[oracle@rh6 dbs]$ su -
Password: 

[root@rh6 ~]# umount tmpfs
umount: /dev/shm: device is busy.
        (In some cases useful info about processes that use
         the device is found by lsof(8) or fuser(1))

关闭和tmpfs相关的process：

?

[root@rh6 ~]# fuser -kc /dev/shm
/dev/shm:             2204m

[root@rh6 ~]# umount tmpfs

[root@rh6 ~]# mount  -t tmpfs shmfs -o size=1300m /dev/shm
[root@rh6 ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda2              18G  5.2G   12G  32% /
/dev/sda1             2.0G   62M  1.8G   4% /boot
/dev/sda3              12G  5.7G  5.4G  52% /u01
/dev/sda5             9.9G  4.9G  4.6G  52% /usr
/dev/sda7             4.2G  300M  3.7G   8% /var
shmfs                 1.3G     0  1.3G   0% /dev/shm

修改fstab文件，当系统启动时mount tmpfs