Add gpbackup install information

Author: tuhaihe

101-cbdb-tutorials/101-6-backup-and-recovery-operations.md

@@ -4,6 +4,9 @@ title: "101 - Lesson 6: Backup and Recovery Operations"
 
 # Backup and Recovery Operations
 
+> [!Note]
+> The Cloudberry Database does not include the utility `gpbackup` by default. It's maintained separately. Please follow the [README](https://github.com/cloudberrydb/gpbackup) to install `gpbackup` before using it.
+
 The parallel dump utility `gpbackup` backs up the CloudberryDB master instance and each active segment instance at the same time.
 
 By default, gpbackup creates dump files in the backups subdirectory.