Delta Backups

[former_member182824]

Hi all,

My name is Man-Ted Chan and I’m from the SAP HANA Product Support team. Today I’m just writing up an add-on to a previous blog and video:

Backup and recovery blog
Storage Snapshot video

This blog will be about a new feature in HANA SP10, delta backups.

What is a Delta Backup?

Starting with SPS 10 delta backups were introduced, this feature allows users to perform backup and recoveries quicker. Delta backups only capture the data changed since the last backup or delta backup, meaning less log backups are read for a recovery.

There are two options available when creating a delta backup:

Differential Backup - stores all data changed since the last full backup.

Incremental Backup - Stores the data changed since the last full or last delta backup. These backups are smaller than the differential backups.

How to Create a Delta Backup?

First choose a user that has the BACKUP ADMIN authorization, in this case we will be using the SYSTEM user.

Right click on the system you would like to create a backup for



In the ‘Backup Type’ select the delta backup options









This error occurred because I did not create full data backup prior to making this delta backup, as mentioned before delta backups are just the difference between the current time to the last full backup. The nameserver trace will show the following:

 

[23117]{300068}[-1/-1] 2016-02-12 20:18:27.643831 i Backup           BackupMgr_DeltaBackupTracker.cpp(00845) :  [DBT] received BackupCatalog_DifferentialBackupStartEntry for 1455308307601

[23117]{300068}[-1/-1] 2016-02-12 20:18:27.644641 i Backup BackupMgr_DeltaBackupTracker.cpp(00113) : No data backups found.

 

After we create a full data backup in the nameserver trace we will see:

 

i Backup BackupMgr_DeltaBackupTracker.cpp(00845) :  [DBT] received BackupCatalog_DifferentialBackupStartEntry for 1455309927467

e Backup BackupMgr_DeltaBackupTracker.cpp(00957) : Requested volume 0 not found in backup tracker.

i Backup BackupMgr_DeltaBackupTracker.cpp(00685) :  [DBT] received BackupCatalog_DataDestinationStartEntry for 1455309927467

1. backup.log will show:

BACKUP   SAVE DATA will write to the following files:

INFO    BACKUP   to file: /usr/sap/xx/HDB00/backup/data/DIFF_DATA_BACKUP_databackup_differential_0_1455309927467_0_1

INFO    BACKUP   to file: /usr/sap/xx/HDB00/backup/data/DIFF_DATA_BACKUP_databackup_differential_1455309613593_1455309927467_1_1
….
INFO    BACKUP   SAVE DATA finished successfully

As we can see the only way to tell it is a differential backup is by the filename

*PREFIX*_databackup_differential

Incremental backups are done the same



And the logs are not much different as it just shows the file name is *PREFIX*_databackup_incremental (IE. INC_DATA_BACKUP_databackup_incremental_0_1455310512146_0_1)

Please note that in SPS 10 you cannot create a delta backup in the HANA Cockpit, but this feature is available in HANA SPS 11

HANA SPS 10 will show the delta backup options as disabled

Viewing Backups

You can view the backups in the HANA Studio by opening the backup wizard



To see our delta backups are not there, to see them we will need to check ‘Show Delta Backups’



Please note in the HANA cockpit the delta backups are not visible and not option to view them (SPS 10>

What About Recoveries?

Recoveries are performed the same as before





Please note that if you choose ‘Recover the database to a specific data backup or storage snapshot’ you won’t have the option to select a delta

Select the log area



Select the data backup



After this we can select the delta backup option



Please note that if you selected ‘Recover the database to a specific data backup or storage snapshot’ this option will be grayed out.