ora-00845解决方法

[oracle@up ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.1.0 Production on Tue Nov 10 19:26:05 2015

Copyright (c) 1982, 2009, Oracle.  All rights reserved.

Connected to an idle instance.

SQL> startup;

ORA-00845: MEMORY_TARGET not supported on this system

SQL> 

错误原因：tmpfs空间不能小于MEMORY_TARGET的值，tmpfs空间太小数据库无法启动

[root@up ~]# vi /u01/app/oracle/product/11.2.0/dbs/init.ora 

db_name='ORCL'

memory_target=1G

processes = 150

audit_file_dest='<ORACLE_BASE>/admin/orcl/adump'

audit_trail ='db'

db_block_size=8192

db_domain=''

数据库参数文件里memory_target参数的大小为1G

[root@up ~]# df -h

Filesystem      Size  Used Avail Use% Mounted on

/dev/sda3        26G   17G  7.4G  70% /

tmpfs           242M     0  242M   0% /dev/shm

/dev/sda1       190M   28M  153M  16% /boot

tmpfs空间大小242M，所以无法启动数据库

解决方法，在/etc/fstab里修改tmpfs的挂载选项，增大tmpfs的空间

[root@up ~]# vi /etc/fstab

UUID=a6948461-a0e3-4e64-bf75-e9a45864d48a /               ext4    defaults        1 1

UUID=0d5a41b3-3988-467f-be75-93e0e4fad1e9 /boot           ext4    defaults        1 2

UUID=bba460fd-bdbe-4a7e-ba49-4016f4633067 swap            swap    defaults        0 0

tmpfs                   /dev/shm                tmpfs   defaults,size=2G        0 0

devpts                  /dev/pts                devpts  gid=5,mode=620  0 0

sysfs                   /sys                    sysfs   defaults        0 0

proc                    /proc                   proc    defaults        0 0

修改tmpfs挂载，将tmpfs空间大小设置为2G

重启系统

[root@up ~]# df -h

Filesystem      Size  Used Avail Use% Mounted on

/dev/sda3        26G   17G  7.4G  70% /

tmpfs           2.0G     0  2.0G   0% /dev/shm

/dev/sda1       190M   28M  153M  16% /boot

更改后tmpfs为2G

[root@up ~]# su - oracle

[oracle@up ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.1.0 Production on Tue Nov 10 19:40:28 2015

Copyright (c) 1982, 2009, Oracle.  All rights reserved.

Connected to an idle instance.

SQL> startup;

ORACLE instance started.

Total System Global Area  409194496 bytes

Fixed Size     2213856 bytes

Variable Size   301991968 bytes

Database Buffers    96468992 bytes

Redo Buffers     8519680 bytes

Database mounted.

Database opened.

问题解决，数据库启动完毕