Back up storage spaces and logical-log files
When you use HDR, you must back up logical-log files and storage spaces only on the primary database server. Be prepared, however, to perform storage-space and logical-log backups on the secondary database server in case the type of the database server is changed to standard.
You must use the same backup and restore tool on both database servers.
The block size and tape size used (for both storage-space backups and logical-log backups) must be identical on the primary and secondary database servers.