Before creating a policy, you should be clear on the requirements of RPO and RTO and its relevant cost implications.
RPO (Recovery-point-objective) indicates how much data loss is acceptable for the user/customer. This is determined by the log backup frequency. More frequent log backups indicate lower RPO and the minimum value supported by Azure Backup service is 15 minutes. So log backup frequency can be 15 minutes or higher.
RTO (Recovery-time-objective) indicates how fast the data should be restored to the last available point-in-time after a data loss scenario. This depends on the recovery strategy employed by HANA, which is usually dependent on how many files are required for restore. This has cost implications as well, and the following table should help in understanding all scenarios and their implications.
Backup policyRTOCost Daily Full + logsFastest, since we need only one full copy + required logs for point-in-time restoreCostliest option since a full copy is taken daily and so more and more data is accumulated in backend until the retention time Weekly Full + daily differential + logsSlower than the above option, but faster than the next option since we require one full copy + one differential copy + logs for point-in-time restoreLess expensive option since the daily differential is usually smaller than full and a full copy is taken only once a week Weekly Full + daily incremental + logsSlowest since we need one full copy + 'n' incrementals + logs for point-in-time recoveryLeast expensive option since the daily incremental will be smaller than differential and a full copy is taken only weekly
Note
The above options are the most common, but not the only options. For example, you can have a weekly full backup + differentials twice a week + logs.
Therefore, you can select the policy variant based on RPO and RTO objectives and cost considerations.