How to avoid Recovery Catalog's metadata being purged after 60 days?
This is described in the note:

How to Clean up The information in EM Backup Report (Doc ID 430601.1)

Edit recover.bsq, find the procedure cleanupRSR, change the default value 60 as needed:

  DELETE FROM rsr
        WHERE rsr_end &lt; nowTime-60
          AND rsr.dbinc_key IN
              (select dbinc_key from dbinc
               where dbinc.db_key = this_db_key);


When finished:

RMAN&gt; upgrade catalog;