Obsolete、Expired

• Obsolete
  根據保留策略而被丟棄時，就會被標記為Obsolete。
  例如:
  設定保留策略
  RMAN> configure retention policy to recovery window of 4 days;
  因此5天前的備份都會被標記為Obsolete。
• Expired
  Crosscheck對備份進行校驗，當備份儲存在RMAN目錄中，但是找不倒備份實體的檔案。
  例如:
  Our controlfile thinks that there is a backup under a directory with a name but someone delete this file from operating system. We can run crosscheck command to check if these files are exist and if rman found a file is missing then mark that backup record as expired which means is no more exists.