## 3.6 Backup And Recovery
This section discusses issues related to backup and recovery and how to troubleshoot them.
## Back and Recovery: Resources
For detailed information on how to perform a backup or recovery of an SAP HANA database please refer to section SAP HANA Database Backup and Recovery of the SAP HANA Administration Guide .
##  Note
Following the configuration information, prerequisites and requirements for your HANA release and revision as documented in the SAP HANA Administration Guide can avoid the most common issues faced by customers when performing a backup or recovery.
Backup and Recovery can be done in SAP HANA studio or in SAP HANA cockpit; refer to the documentation for these administration tools for details.
The following links to the SAP HANA Support Content provide a step-by-step description with detailed screenshots of how Backup and Recovery can be executed from SAP HANA studio:
- How to Perform a Backup
- Recovery
In addition to the SAP Notes and Knowledge Base Articles referred to in this section, the following may also be useful:
- SAP Note 1642148 - FAQ: SAP HANA Database Backup & Recovery
- SAP Note 2116157 - FAQ: SAP HANA Consistency Checks and Corruptions
- SAP KBA 2101244 - FAQ: SAP HANA Multitenant Database Containers (MDC)
- SAP Note 2096000 - SAP HANA multitenant database containers - Additional Information
- SAP KBA 2486224 - T enant DB recovery to another system Tenant DB
- SAP Note 2093572 - SAP HANA Migration from Multi-Node to Single-Node
- SAP Note 1730932 - Using backup tools with Backint for HANA
- SAP Note 1651055 - Scheduling SAP HANA Database Backups in Linux
- SAP Note 2044438 - HANA: Backup fails for Out Of Memory error
- SAP Note 2123153 - HANA Recovery Failing with 'recovery strategy could not be determined'
- SAP Note 2063454 - Long running log backups
- SAP KBA 2495074 - Recovery failed with data backup file of higher HANA revision
- SAP KBA 1990971 - HANA backup failed with 'Wrong Checksum' error
- SAP Note 2605215 - Replay of Logs Hanging During Point in Time Recovery or Operations on System Replication Secondary Site
## Logs and Trace Files
In most cases for both backup and recovery issues a relevant error message will be written to the following SAP HANA database log or trace files:
- backup.log
- namesever.trc
- backint.log (if using backint and 3rd party tool)
These log and trace files (diagnostic files) can be found using SAP HANA studio, DBA Cockpit, and SAP HANA Database Explorer. The default location for the files is:
/usr/sap/&lt;SID>=/HDB&lt;Instance#>=/&lt;host>=/trace
You can search for either backup or recovery tasks which generate an error in the backup.log file by referring to the task type and the date and time that the issue occurred:
```
2018-09-26T06:58:11+00:00 16614abbef0 INFO  BACKUP SAVE DATA started 2018-08-29T09:45:52+00:00 1658510b5bb ERROR BACKUP SAVE DATA finished with error: [447] backup could not be completed ….rc=28: No space left 2018-08-29T09:45:52+00:00 1658510b5bb INFO  BACKUP state of service…
```
With the error code and error message you can search for SAP Notes and Knowledge Base Articles in the SAP Knowledge Base using SAP ONE Support Launchpad
## Increasing the trace level
Although in most cases it should not be necessary to use the debug trace level to find the relevant error message, if the standard trace level for the backup.log file does not return a meaningful error message you can temporarily set the level to 'debug' using the following commands:
Enable the trace:
```
ALTER SYSTEM ALTER CONFIGURATION ('global.ini', 'SYSTEM') SET ('trace', 'backup') = 'debug' with reconfigure;
```
Disable the trace:
```
ALTER SYSTEM ALTER CONFIGURATION ('global.ini', 'SYSTEM') UNSET ('trace', 'backup') with reconfigure;
```
## Common Issues Related to Backup and Recovery
Some of the most common issues are described here.
## Log Volume Full
The symptoms of a log volume full are:
- Alert #2 is generated, for example: "Alert disk usage" for "storage type: LOG".
- The database cannot be started or does not accept new requests.
- The database trace file of a service contains rc=24 no space left on device errors for the basepath_logvolumes or basepath_logbackup .
##  Note
Note that when a cluster file system like HP IBRIX or IBM GPFS is used, HANA Studio or OS commands like df -h might not detect a problem. In this case use the filesystem specific commands like mmdf/ mmrepquota for IBM GPFS.
In this situation reasons for data and log backups failing may include:
- Backup location for data and log backup is the same location as data and log volumes and space runs out
- Automatic log backup parameter is not enabled (enable_auto_log_backup). If automatic log backup is disabled, the log area grows until the file system is full. If the file system is full, the database will remain frozen until the situation is resolved.
See the following SAP Notes for troubleshooting details in this case:
- 2083715 -Analyzing log volume full situations .
- 1679938 -Disk Full Event on Log Volume .
## Large Size of Log Backup Files
The backup catalog stores information about the data and log backups that were executed for a database and the catalog is backed up as part of the log backups. If you do not ensure that old backups are deleted in accordance with backup and recovery strategy the log backups can become increasingly large over time.
For information on the clean-up of the backup catalog see the following:
- Housekeeping for backup.log and backint.log in the SAP HANA Administration Guide
- KBA 2096851 -Backup Catalog Housekeeping within HANA DB
- KBA 2505218 -Large Log Backups due to large backup catalog
## Regular manual consistency check of backups required for SAP HANA Database Recovery
Although HANA has automatic checks that take place while data and log backups are performed you should manually re-check the integrity of any backup if it is copied or moved to another location or if you need to use the backup files for HANA database recovery. This manual check can be done using hdbbackupcheck .
For information on the usage of the hdbbackupcheck command see the KBA 1869119 -Checking backups with 'hdbbackupcheck'
## Problems With Backint and 3rd Party Backup Tools
SAP HANA comes with native functionality for backup and recovery but using 3rd party backup tools is an alternative to using the native functionality. SAP HANA database provides a backup interface called Backint which enables 3rd-party backup tool vendors to connect their product to the backup and recovery capabilities of the SAP HANA database. Backint is fully integrated into the SAP HANA database, that is, data and log backups can be individually configured to be created and recovered using the 3rd-party backup tool. Backups are transferred via named pipe from the SAP HANA database to the 3rd party backup agent, which runs on the SAP HANA database server and then sends the backups to the 3rd party backup server.
For more information on SAP HANA backup and recovery and the integration of 3rd party backup tools with SAP HANA, please refer to:
- The SAP HANA Administration Guide
- The installation documentation for 3rd party backup tools provided by the tool vendor
- SAP Note 2031547 -Overview of SAP-certified 3rd party backup tools and associated support process
If you face an issue with a 3rd party backup tool check SAP Note 2031547 to confirm that the backup tool is supported. If the tool is supported the next step is to check for error messages in the backint.log file as described above. Follow the appropriate support process for the tool as described in this SAP note.
As a workaround for a problem with a 3rd party backup tool, and if you have the required disk space, you could use the SAP HANA native functionality for backup.
## Backint Pipe Size
A cause of slow performance related to backint and SUSE Linux Enterprise Server 15 SP4 may be related to the default pipe size. Due to a change in the default configuration of the maximum size of a pipe in the operating system, the data transfer rate of backint may be restricted. In HANA 2.0 SPS 07 (072.00) a configuration parameter was introduced which makes it possible to set the pipe capacity. The parameter backint_pipe_capacity (in the backup section of the global.ini file) is not active by default but can be set to a number of bytes to override the default capacity of the operating system. Further details and examples of how this can be applied are given in SAP Note 3417100 -HANA Database Backup or Recovery using Backint for SAP HANA is very slow .
## HANA BACKUP and Recovery Performance
In many cases, problems with backup and recovery performance are related to non-optimal system I/O or the backup catalog size.
To check the HANA I/O performance refer to the Knowledge Base article 1999930 -FAQ: SAP HANA I/O Analysis . Regarding the backup catalog refer to the subsection above Large size of Log Backup files .
To analyze performance problems related to backup and recovery you can also refer to the guided answer Troubleshooting Performance Issues in SAP HANA , if the guided answer does not provide a solution for further analysis SAP Support would require the information in the SAP Note 1835075 -Analyze backup and recovery performance issues .
## Related Information
SAP HANA Database Backup and Recovery (SAP HANA Administration Guide)