HANA point-in-timhe recovery issues

[Former Member]

We are facing issues with the point-in-time recovery for SAP-HANA SPS08 REV82 systems.

We needed to know the below details for the point-in-time recovery.

Consider we have taken the full backup on SAP-HANA system at around 10:00 and backup is completed at 10:10 hrs, then do we need the log backups generated between 10:00 to 10:10 hrs for the point-in-time recovery

we are getting these error for the same

Backup /backup/log/<SID>/log_backup_3_0_4066106368_4066193856.1431338580258 does not exist

Backup /backup/log/<SID>/log_backup_4_0_7961187072_7961521024.1431377581666 does not exist 

[Former Member]

I think you are talking about two separate things here.

Consider we have taken the full backup on SAP-HANA system at around 10:00 and backup is completed at 10:10 hrs, then do we need the log backups generated between 10:00 to 10:10 hrs for the point-in-time recovery

>> Yes, you will need the log backup files for point in time recovery for the 10 minutes. However, the log backup is enabled after the first initial data backup and the log backup is done automatically by default and throw the log backup files to the DEFAULT location. I think it is ../backup/log in the HANA instance directory.

we are getting these error for the same

Backup /backup/log/<SID>/log_backup_3_0_4066106368_4066193856.1431338580258 does not exist

Backup /backup/log/<SID>/log_backup_4_0_7961187072_7961521024.1431377581666 does not exist 

>> To me this is more like the backup file got deleted or moved from the original location to other location.

[sadanand_bhat]

Hi Somayya,

Can you check and tell whether below log backups exist:

Backup /backup/log/<SID>/log_backup_3_0_4066106368_4066193856.1431338580258 does not exist

Backup /backup/log/<SID>/log_backup_4_0_7961187072_7961521024.1431377581666 does not exist

If not, check in backup catalog whether they exist? You can open backup console in Studio and in the history of log backups you can check whether do they exist!

We can suggest you then

Best Regards,

Sadanand Bhat

[Former Member]

HI Somayya,

are you Performing the Recovery beyond 10:10 ?

If yes, then we need the log backup.

Regards,

Pavan Gunda

[Former Member]

Pavan i am using the point-in-time recovery using the last full backup which was taken at 10:00 hrs and applying the logs later to that.

This is the scenario that we are using for the backup restore.

[Former Member]

We need the log backups for the point-in-time recovery i am aware of that but my question is different. Genarally we apply the latest backup and then the logs starts to apply after the backup time.

Consider I am executing the backup for HANA on 2015 Jan 12 at 10:00 hrs and it takes 8 Minutes to complete the backup so the backup will be completed at 10:08 hrs

Then the HANA Backup is stored under directory example: 201501121000 so the previous backups will be stored in 201501111000

The log backups which are generated after the backup will be stored in the directory 2015Jan12 again these are managed by the scripts,

the log backups which are generated during the backup or before the backup will be stored in the previous directory 201501111000

For example the LOGS_XYZ generated at 10:02 and LOGS_ABC generated at 10:07

So now when we are doing the point-in-time recovery for the HANA system using the backup folder 201501121000 we get an error stating LOGS_ABC and LOGS_XYZ are missing.

So do we need the logs generated between the backup time for the point-in-time recovery as it should be in the full backup itself right.

[Former Member]

Hi Somayya,

PIT in Hana will be checking for the log backups that are not required. PIT recovery will read the last log backup that is present in the log backup directory. I have encountered the same situation in HANA SPS07 and raised my concern to SAP.

SAP mentioned that they will be correcting this logic in the latest version SPS09 (may be 96 i believe).

Regards,

Pavan Gunda

[Former Member]

Hi Sommaya,

In HANA the Data backup that is taken at 10:00 AM inlcudes changes made on the Database only until 10:00 AM

Let us say the Data backup completed at 10:10 AM, the subsequent transaction logs generated between 10:00 AM and 10:10 AM need to be recovered if you need a PIT until 10:10 AM

This logic is different with other RDBMS that inlcude all changes from the point the backup is triggered until the point the backup completes

Hope the explanation is clear

Sunil

[Former Member]

When we are doing a PIT recovery from the SAP HANA Studio we use the check option Initialize Log Area, can anyone define it what is the use of that and what actions it performs.

Is it really needed for us to check the option Initialize log area.

[Former Member]

This option is useful to recovering a HANA Database whose log area is unusable as it prevents the recovery of entries from the unusable log area I do not think you will need to use this option unless your HANA Database crashed and you are trying to recover it until the point it crashed.... For a regular PIT recovery to an old state of the Database from the backups you do not need this option

[Former Member]

check the SAP note 1779221: Recovery of HANA Database fails for more information

https://websmp130.sap-ag.de/sap(bD1lbiZjPTAwMQ==)/bc/bsp/sno/ui_entry/entry.htm?param=69765F6D6F6465...

[mathanponnucham]

Dear Sowmayya,

SAP HANA system was right in asking for the LOGS_ABC and LOGS_XYZ files.

I would recommend you to read SAP HANA Backup/Recovery Overview document.

Slides 9 will explain you a savepoint is created when a backup is triggered, which means backup only has content before that save point.

Slide 23 explains the different recovery scenarios. In user case I believe you were trying for option A which means you will need backup + all log files generated after this backup is triggered + entries that are available in the log area.

Rgds,

Mat.

[Former Member]

Hi Somayya, With regards to your issue I understand that you have taken Online backup. If that is offline I think then there is no point of talking about the log backup. If it's Online yes you need to have log backup to be applied from 10 - 10:10 hrs for point -in - time recovery. with regards to error, can you please provide more details with screenshot to understand on same. Cheers Deepanshu Sharma