Identifying Database Copy Scenarios

You can create a homogeneous copy of an SAP HANA database by using backups of that database to recover to the same system or a different system. A homogeneous database copy is a quick way to set up a cloned database, for example, for training, testing, or development.

You can use backup and recovery to copy a system database or a tenant database within the same system or to a different system. You can create a copy of a database using a complete data backup or a data snapshot. Also, using delta backups (differential or incremental backups) and log backups allows you to copy the database to a specific point in time.

Copy a Database Using a Database Backup

You can copy an SAP HANA database using file-based backups or backups created using third-party tools.

Note

The backup catalog, the data backups, and the log backups must be from either only a third-party backup tool or only the file system.

(For a standard database recovery, it is possible to use a combination of backups from a third-party tool and the file system, provided that the backups originate from the same SAP HANA database.)

Using the SAP HANA cockpit, you can create a copy of an SAP HANA database by using backups of that database to recover to the same system or a different system.

If you are copying a database using a full data backup only, you can either select the data backup from the backup catalog, or specify its location without using a backup catalog.

A copy to a point in time is not possible if the full data backup is not recorded in the backup catalog.

Copy a Database Using a Data Snapshot

Prerequisites

• For a database copy using data snapshots, the number of hosts and the number and type of services assigned to each host must be the same for the source database and the target database, and the mountpoint IDs must be identical.
• Using a data snapshot, it is only possible to copy an SAP HANA system with one tenant database.
• When you recover SAP HANA from a data snapshot, you need to recover both the system database and the tenant database.
• To copy SAP HANA from a data snapshot, you first need to stop the target SAP HANA database, then make available the data snapshot in the data area of the target database.

Note

If you attempt to use a data snapshot to copy an SAP HANA system with more than one tenant database, this may make the data area for all the tenant databases unusable.

Database Copy from System with m Nodes to a System with n Nodes

You can copy an SAP HANA database system with m nodes to an SAP HANA database with n nodes. This is useful for when you want to use a copy of your production system for tests on a smaller QA system, for example.

In the following examples, the source database and the target database are both tenant databases.

Target Database Has Fewer Hosts Than the Source Database

Example: The source database has two hosts, each with one index server. The target database has only one host.

All content of the data backup is recovered to the target host.

The target database now holds the data of the two hosts from the source database, and there are two index servers on the single-host target database.

Target Database Has More Hosts Than the Source Database

Example: The source database has two hosts, each with one index server. The target database has three hosts.

• All content of the backup is recovered to the two existing hosts.

  At this stage, the third host in the target system remains unused.

• After the recovery, you can distribute all the data in the target database from the two hosts to the three hosts that are now available.

• A database with three hosts has been created, containing the data from the previous two-host database.

You can use the SAP HANA database lifecycle manager (HDBLCM) to make a copy or a clone of an SAP HANA system by copying the file system containing the SAP HANA database installation from an old storage solution to a new storage solution, and registering the copied SAP HANA system on new hosts.

Before cloning the SAP HANA system, you must create a physical copy of the SAP HANA system (storage snapshot, file systems copy). The source system must be offline or a database snapshot must have been taken on the source system before the physical copy of the SAP HANA system is created.

Cloning an SAP HANA system produces a new SAP HANA system, identical to the existing one. Copying an SAP HANA system produces a new SAP HANA system with the same landscape as the existing one, but with slightly different parameter settings. If the interactive parameter defaults are accepted during host registration, the system is effectively cloned. If the new system parameters are set to different values, the new system is similar, but not identical to the source system.

You could, for example, copy an existing production system, and accept all parameter defaults during host registration except system_usage, which would be specified as "test". This configuration would allow you to have an almost identical copy of the existing system for test or quality assurance purposes.

To clone an SAP HANA system to new hardware, follow these steps:

1. Copy the file system to the new storage
2. Mount /hana/shared to the new hosts
3. Register the copied SAP HANA instances on the new hosts using -action=register_rename_system

Copying and moving tenant databases between systems allows you to manage your system landscape efficiently and to respond flexibly to changing resource requirements. Therefore, SAP HANA uses system replication mechanisms. These mechanisms allow you to copy and move tenant databases securely and conveniently with near-zero downtime.

First, the tenant database is copied with all of its data to a newly created tenant database in a target system.

The only difference between copying and moving a tenant database therefore is what happens to the original tenant database after all data has been transferred to the new tenant database in the target system.

In both cases, the new tenant database starts running as a fully separate, independent database.

Several tenant databases can be copied or moved to a system at the same time. It is also possible to copy or move a tenant database to a system with a different isolation level than the source system.