RMAN-08138: WARNING: archived log not deleted - must create more backups

RMAN-08138: WARNING: archived log not deleted - must create more backups 

• 1.       You should check your deletion_policy (if you delete with obsolete commad you should look at your retention policy)

• 2.       It could be expired, so to delete archivelog :

                  delete noprompt expired archivelog all;

• 3.       You could have given a unique name while taking backup, so you should correct it :

               Backup as copy tag = “unique_%d_%U” plus archivelog