Standby archive apply hang due to space issue

Ideally at designing stage we should have allocated sufficient space for both PROD and STANDBY and they should match. For example, if a file system U05 is 500GB on PROD you should size the file system to 500GB on STANDBY as well. 

Well but not always. :)

We hang on issue when a DBA had added a datafile in Prod at U05 file system but due to lack space at DR Side for file system U05, archive apply stopped.

Standby_file_management is set to auto.

It was noted when archive apply was stopped due to space issue. 

Because is the steps taken to carried away: 

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL; 

SQL> ALTER SYSTEM SET STANDBY_FILE_MANAGEMENT=MANUAL; 

SQL> ALTER DATABASE CREATE DATAFILE '/u01/app/oracle/11.2.0/db_1/dbs/UNNAMED00143' AS '/u06/realfilename/gdata05.dbf'; 

SQL> ALTER SYSTEM SET STANDBY_FILE_MANAGEMENT=AUTO; 

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT; 

or, If you are using real time apply (it makes use of standby redo log file) 

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT; 

Hope this helps...