Merge pull request mendix#8798 from mendix/MvM-BackupSize

Warn against trying to use tools to reduce database size

Author: MarkvanMents

content/en/docs/deployment/mendix-cloud-deploy/backups/database-size-reduction.md

@@ -22,6 +22,10 @@ However, there may be times when physically reclaiming the lost space is importa
 
 You can recover physical disk space by creating a database backup and then restoring it.
 
+{{% alert color="warning" %}}
+Do not try to manipulate the backup in any way to reduce its size before restoring it. Doing so may lead to a backup file which can no longer be restored.
+{{% /alert %}}
+
 A database restore does a full physical rewrite of the database. It compresses the database to contain just the current records. It also fully optimizes the physical placement of files on the actual hard disk to maximize the performance of disk read operations.
 
 In the Mendix Portal, you can create and restore a backup on your app's **Backups** page. For more information, see [Creating a Backup](/developerportal/operate/create-backup/).

content/en/docs/deployment/mendix-cloud-deploy/backups/restore-backup.md

@@ -107,6 +107,10 @@ Contact [Mendix Support](https://support.mendix.com/) if you need further assist
 
 You may want to restore a backup that has been created on another platform (for example, an on-premises deployment). In this case, you will have to construct a backup file that Mendix Cloud will recognize. It is possible to upload a **Database Only** or **Full Snapshot** backup file.
 
+{{% alert color="warning" %}}
+Any local manipulation you perform after creating a backup is at your own risk. You may end up with a backup file which cannot be restored.
+{{% /alert %}}
+
 ### Database Only Format{#database-only}
 
 A **Database Only** backup file is a *.backup* file (for example, *database-fc9e126f-201811210121.backup*).