Outlining Backup and Recovery Options in SAP HANA Database

An SAP HANA database stores all the data for SAP applications such as SAP S/4HANA, SAP SuccessFactors, or SAP BW/4HANA. This data is important to your organization, and it is vital that this data be protected against possible data loss.

SAP HANA supports a number of techniques which can prevent data loss, maintain a high level of availability, and mitigate disasters. The most important of these techniques is database backup. These techniques are similar to reliability methods in other databases, such as SAP ASE, Oracle, IBM DB2, and so on.

System Administrators are responsible for database backups and restores. However, they typically don't perform the backups themselves. Instead, backups are set up to run automatically by job scheduler software. These backups are stored in a safe place for possible future use.

When necessary, System Administrators can restore these backups to an SAP HANA database. This could be because:

• To create a copy of data at an earlier point in time, for historical, reporting, or regulatory reasons.
• An error has occurred that requires data to be recovered.
• The server host has failed, and a new server must be set up.
• Your data center has suffered a disaster.

Most software applications run normally, with few or no problems. But occasionally, things go wrong. Sometimes, they go very wrong.

On Monday, April 13, 1992, water started pouring into the basements of buildings in downtown Chicago. A company dredging the Chicago River had accidentally broken through the roof of a tunnel system that ran under the river and the downtown area. 124 million gallons of water flowed into this tunnel and nearby buildings' basements.

Several Chicago banks had their headquarters in these buildings. Some of them, unfortunately, kept their data centers in the basement. The computers in these data centers were completely destroyed. The buildings were evacuated, and all operations (including computer operations) ceased. The overall damage was estimated at over $2 billion, not counting the downtime that their systems experienced.

Once the flood was stopped, these banks had to resume operations. Fortunately, they had prepared for a crisis. They had alternative data centers elsewhere in Chicago and in other cities. They could restore from their backups and continue operating.

While this sort of thing doesn't happen every day, every organization must be prepared for the worst. They must define a backup strategy and backup procedures that will allow data recovery and resumption of normal operations. All of this must be done before a problem starts.

The most important responsibility of a System Administrator is to create a backup strategy. The decisions may include:

• How often will backups be performed?
• What types of backups are needed?
• Where will the backup files be stored? For how long?
• What backup features will be used, such as compression, encryption, incremental backups, and so on?
• What tools will be used to perform backups?
• Who is responsible for monitoring backups? Who is notified in case of problems?

These decisions should ensure:

• The data is safe from the possibility of data loss.
• The backed-up data is accessible when needed.
• The backup process is efficient and not intrusive.
• The backup process is consistent with the customer's operational standards.

Backups must be performed on a regular basis, so that new data captured by the application is kept safely. They must be frequent enough not to lose transactions that have recently been entered.

System Administrators typically do not perform manual backups. Instead, they use job scheduler software to set up a backup schedule. This software will execute backups and allow System Administrator monitoring.

SAP provides a variety of useful job schedulers, including one in SAP HANA cockpit. Third-party job schedulers are also available, such as cron in the Linux operating system.

When the backup executes, it creates files containing the backed-up data. These files are typically copied to a storage management systems, such as Google Cloud Storage, Microsoft Azure Backup, Commvault, and so on. It is the responsibility of the System Administrator to ensure that the files are stored safely and securely, and retained for the appropriate length of time.

SAP HANA keeps all its data in memory, but also writes it to disk. If the database crashes, the server can be restarted, and the data on disk can be loaded back into memory.

However, if there's a bigger problem, such as a disk fault, data corruption, or a server that cannot be restarted, restarting the database would not be sufficient. The System Administrator would have to recover the database from a backup.

The database recovery process can:

• Re-create a database in-place.
• Restore the data on a new database server.
• Copy a database to a new location.

The process is typically done manually, after any problems or errors have been corrected. Once the restore is complete, the database will be accessible to application users, and normal operations can continue.

Well done, backup and recovery principles in SAP HANA Database are not a secret for you anymore.