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Backup Types in Hana



How Backup and Recovery Works in SAP HANA?



To protect against data loss due to disk failures, backups are required. Backups save the data of the data area and log area to different locations (configurable). Currently only backups to the file system are supported.

1> Full Backup
    a> Data backup
    b> Storage snapshot (Snapshot Backup)

2> Delta Backup
    a> Incremental backup
    b> Differential backup

3> Log Backup

Following are the components for backups which requires to restore the database in case of recoveries.

  Data Backup :

To perform a data backup, the database system must be in operational state (online). Initially a backup request is received by one of the Index Servers and forwarded to the backup manager in the Master Name Server. The backup manager first tells all participating servers to perform a global savepoint. The global savepoint is required to get a system wide-consistent snapshot of the database.

Backup controllers have to get the data from the pages stored in the data volumes on disk. This is necessary because we need to back up the consistent state written during the global savepoint operation.

  Log Backup :

SAP HANA Database supports automatic log backup. Automated log backup is a local process which is triggered and executed by each server in the SAP HANA database system autonomously. It is performed when a log segment is full, when a configured time limit is exceeded or after startup of a server. The time limit is required to ensure that logs are backed up from time to time even if there are few changes and the log segments are not filled. This is especially important with distributed transactions.


The SAP HANA database is a distributed system. It consists of multiple servers with their own persistence: Name Servers, multiple Index Servers, and a Statistics Server. It is important that during recovery the system is restored to a state that is consistent across the whole system.

Data Backup and Log backup can be configured using following parameters in global.ini
           
Parameter
Options
Log_mode
 normal / overwrite / legacy
Enable_auto_log_backup
 yes / no
log_backup_timeout_s

basepath_logbackup
 xyz/hdb/SID/backup/log
basepath_databackup
 xyz/hdb/SID/backup/data
basepath_datavolumes
 xyz/hdb/SID/data
basepath_logvolumes
xyz/hdb/SID/log

Figure 1. List of backup parameters to be configured in global.ini

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