Memory_target not supported on this system error is reported when the oracle11g database is started.

When the oracle11g database is started, the memory_target not supported on this system error solution is reported. The reason is that the shm size of the Linux system is smaller than that set by the SGA. In terms of distance, SGA is set to 4 GB, shm may only provide two solutions on the 1G network: 01. Adjust the size of the sga. This is obviously not the expected 02. Adjust the size of the shm. This is relatively simple, follow these steps to modify tmpfs/dev/shm tmpfs defaults 0 0 to tmpfs/dev/shm tmpfs defaults, size = 6G 0 save and exit re-mount the shm to make it take effect mount-o remount/dev/shm can be viewed through df, if there is no problem, you can continue to install the database or start the database! Note: There are two different database instances on the server. It is okay when you start an instance. A ORA-00845 error is reported when the second INSTANCE is started. The test server only has 8 GB memory. Tmpfs is 4G 4.0G 1.6G 2.4G 40%/dev/shm by default. the memory usage of the two instances should exceed 4 GB, so the problem is solved after installing the online article to modify tmpfs. But how can we determine the size limit of tmpfs? Let's take a look at the memory usage. [oracle @ BJRMANTS ~] $ Su-rootPassword: [root @ BJRMANTS ~] # Vi/etc/fstab [root @ BJRMANTS ~] # Df-gdf: invalid option -- 'G' Try 'df -- help' for more information. [root @ BJRMANTS ~] # Df-hFilesystem Size Used Avail Use % Mounted on/dev/sda2 20G 5.8G 13G 31%/tmpfs 4.0G 1.6G 2.4G 40%/dev/shm/dev/sda1 485 M 51 M 409 M 12%/boot/dev/sda6 197G 160G 28G 86%/orabak/dev/sda8 20G 6.2G 13G 34%/oracle/dev/sda5 690G 549G 106G 84%/oradata/dev/sda7 187G 75G 104G 42%/oralog [root @ BJRMANTS ~] # Umount/dev/shm sometimes encounters a situation where/dev/shm cannot be detached # umount/dev/shmumount:/dev/shm: device is busy. use fuser to process # fuser-km/dev/shm # umount/dev/shm # mount/dev/shmfuser command-k: kill processes accessing the named file (killing all processes that are accessing the specified file)-m indicates the file system or block device where the specified file is located (in the mount State ). All processes accessing the file system are listed. [Root @ BJRMANTS ~] # Df-hFilesystem Size Used Avail Use % Mounted on/dev/sda2 20G 5.8G 13G 31%/tmpfs 6.0G 1.6G 4.5G 26%/dev/shm/dev/sda1 485 M 51 M 409 M 12%/boot/dev/sda6 197G 160G 28G 86%/orabak/dev/sda8 20G 6.2G 13G 34%/oracle/dev/sda5 690G 549G 106G 84%/oradata/dev/sda7 187G 75G 104G 42%/oralog Connected: oracle Database 11g Enterprise Edition Release 11.2.0.3.0-64bit ProductionWith the Partitioning, OLAP, Data Mining and Real Application Testing optionsSQL> shutdown abort; ORACLE instance shut down. SQL> exitDisconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.3.0-64bit ProductionWith the Partitioning, OLAP, Data Mining and Real Application Testing options [oracle @ BJRMANTS ~] $ Sqlplus/as sysdbaSQL * Plus: Release 11.2.0.3.0 Production on Wed Dec 5 10:49:51 2012 Copyright (c) 1982,201 1, Oracle. all rights reserved. connected to an idle instance. SQL> startup; ORACLE instance started. total System Global Area 814227456 bytesFixed Size 2232760 bytesVariable Size 452988488 bytesDatabase Buffers 352321536 bytesRedo Buffers 6684672 bytesDatabase mounted. database opened. SQL> exitDisconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.3.0-64bit Production