Have updated some configuration  in Oracle server, Once its done just tried to restart Oracle Server. Shows an error when start SQL server using startup command,

#  sqlplus sys/password  as sysdba

SQL> shutdown immediate

SQL> startup

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

solution :

We need to increase memory_target space from init.ora and spfileXE.ora file.
To find Oracle HOMEPATH and update it.

# cd /u01/app/oracle/product/11.2.0/xe/dbs

# vim init.ora
#  spfileXE.ora

Finally restart your Server,

SQL>  startup

# /etc/init.d/oracle-xe start