Memory_Target or Share_Memory Not Supported

Occasionally I have come across instances where during the process of migrating the virtual machine, something gets messed up and starting Oracle results in the following error:

MEMORY_TARGET NOT SUPPORTED

or

SHARED_MEMORY Realm does not exist

Luckily, it is a fairly straightforward fix.

1. Login as root user

   1. sudo su

   2. Enter ‘cangetin’ as password
2. Change the size of /dev/shm

   1. mount -o remount,size=4G /dev/shm

3. Make the change permanent for next time
   1. Install gedit to edit the file: yum install gedit -y

   2. gedit /etc/fstab

   3. Add the following line to the end of the file

   4. tmpfs /dev/shm tmpfs size=4g 0 0

   5. Select save
4. Login as oracle user

   1. su oracle

5. Login to SQL*Plus

   1. sqlplus / as sysdba

6. Startup the database

   1. SQL> STARTUP

7. Exit back to the student user.