2499913 - How to shrink SAP HANA Data Volume size

Symptom

• You want to free unused space inside an SAP HANA database disk persistence;
• You observe low percentage of Used/Total Size(%) of the Data Volume;
• The Total Size of the Data Volume is too much larger than the Used Size;

Environment

SAP HANA, platform edition

Cause

The data volume is fragmented. You can get more information about in KBA 2400005, point "6. Why can the persistence become fragmented?".

Resolution

The following statement reduces data volume size to a percentage of payload size:

ALTER SYSTEM RECLAIM DATAVOLUME Statement (System Management)

This statement works in a similar way to defragmenting a hard drive: pages that are scattered around a data volume are moved to the front of the volume, and the free space at the end of the data volume is truncated.

Syntax

ALTER SYSTEM RECLAIM DATAVOLUME [SPACE] [<host_port>]    <percentage_of_payload_size> <shrink_mode>

In case the database cannot be accessed via SAP HANA Studio or SAP HANA Cockpit, you can try to reclaim the data volume by using hdbcons:

hdbcons 'dvol shrink -o <overhead_pct>'

Please note that this option can't be used for defragmenting the secondary site of an SAP HANA System Replication system. In case you need to reclaim disk space in the data volume of a secondary site, please refer to KBA 2348397.

See Also

• KBA 3636613 - How to reduce table and /hana/data size
• KBA 2332284 – Data volume reclaim failed because of snapshot pages
• KBA 2400005 – FAQ: SAP HANA Persistence
• KBA 1870858 – HANA Alerts related to file system utilization
• KBA 2222218 – FAQ: SAP HANA Database Server Management Console (hdbcons)

Keywords

shrink, HANA, Data volume, ALTER SYSTEM RECLAIM DATA VOLUME, reduce, shrinking, datavolume, datavol, dvol, persistence, fragmented, fragmentation, defragmentation, defragmenting

 

2984269 - How to cancel DATAVOLUME RECLAIM activity