ORA-00838: Specified value of MEMORY_TARGET is too small, needs to be at least 4128M

Error:

ORA-00838: Specified value of MEMORY_TARGET is too small, needs to be at least 4128M

Cause: The specified value of MEMORY_TARGET was less than the sum of the specified values for SGA_TARGET and PGA_AGGREGATE_TARGET.

Action:

1.  Take a backup PFILE

2.  SQL>CREATE PFILE FROM SPFILE;

3.  Manually Edit the MEMORY_TARGET to at least the recommended value

4.  SQL>CREATE SPFILE FROM PFILE

5.  instance start again

     SQL>startup