ORA-00845: MEMORY_TARGET not supported on this system

系统：一台linux 

内存：1G

数据库1：YANG

数据库2：XU

SYS@YANG>startup
ORA-00845: MEMORY_TARGET not supported on this system

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ORA-00845: MEMORY_TARGET not supported on this system

Cause: The MEMORY_TARGET parameter was not supported on this operating system or /dev/shm was not sized correctly on Linux.

Action: Refer to documentation for a list of supported operating systems. Or, size /dev/shm to be at least the SGA_MAX_SIZE on each Oracle instance running on the system.

由于在一台虚拟机上装了两台数据库，可能是内存争用得问题

验证：

[oracle@YANG dbs]$ cat spfileYANG.ora 

*.memory_target=847249408

[oracle@YANG dbs]$ df -h
Filesystem                       Size  Used Avail Use% Mounted on
tmpfs                           1012M  272M  740M  27% /dev/shm

实例YANG共享内存需要800M左右，但空闲内存只有740M，导致报错

由于安装XU之前，YANG一直是open状态

[oracle@YANG dbs]$ cat spfileXU.ora 

*.memory_target=445644800

SYS@XU>shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SYS@XU>

[oracle@YANG dbs]$ sqlplus / as sysdba


SQL*Plus: Release 11.2.0.1.0 Production on Thu Mar 2 02:40:22 2017


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


Connected to an idle instance.


SYS@YANG>startup
ORACLE instance started.


Total System Global Area  845348864 bytes
Fixed Size                  1339796 bytes
Variable Size             599789164 bytes
Database Buffers          239075328 bytes
Redo Buffers                5144576 bytes
Database mounted.
Database opened.

SYS@XU>startup
ORACLE instance started.


Total System Global Area  447778816 bytes
Fixed Size                  1337128 bytes
Variable Size             297797848 bytes
Database Buffers          142606336 bytes
Redo Buffers                6037504 bytes
Database mounted.
Database opened.
SYS@XU>

调整一下启动顺序，问题解决。