Resolving ORA-00845: MEMORY_TARGET not supported on this system

This error occurred when we tried to start Oracle 11g database.First time database came up without any issues.But when we tried to startup the database after few database, the above issue is thrown.

ORA-00845: MEMORY_TARGET not supported on this system

The above error will normally be thrown when the available memory in /dev/shm or tmpfs is not sufficient. If the above screenshot is observed, available memory for /dev/shm is 1.2G.

Run the command df -h to get the above information.

Now to find the value to which /dev/shm [tmpfs] size has to be increased, open the oracle alert log.

The above information in alert.log mentions the size to be 1.49GB.

Considering this 1.49GB requirement, we set the new size to 3GB in /etc/fstab file.As shown in the picture below, replace defaults with the required size.i.e size=xxxx

Reboot the machine now.

Run df -h to see the changes

Now try to startup database again....