on 08-08-2016 10:56 AM
Dear Team,
We are facing memory issue in our hana box.
On this Box, we have 2 devlopment and 2 quality instances. Along with those we have 2 PRD DR instances. The whole box is of 757GB RAM and 24GB SWAP. Out of which we have limited the ram usage on this different instances using global_allocation_limit paramter as below
Allocated Peak used memory
DEV1 - 125G 75G
QAS1 - 275G 200G
DEV2 - 125G 75G
QAS2 - 175G 110G
LIL PRD DR - 349.95G
LDK PRD DR - 230G
When the dev and quality instances are running, there is no problem of memory. But when once the DR of both the prd instances are setted (configured) the swap is also being utilized with free RAM going to 1 GB.
After some time when less load on dev or quality is happening, the RAM might get release but the swap remains the same 24GB used.
DR is configured with Delta shipping and ASYN mode
HANA version is HANA 1.0 SPS110
Can we reduced the already allocated memory if needed in that development and quality instances.
Kinldy suggest solution.
Hi Vikram,
Please set parameter global.ini/[system_replication]-> preload_column_tables=false on the secondary to switch off preload of tables.
Additionally, set global.ini/[memorymanager]-> global_allocation_limit to a minimum value of 64 GB or “row store size+ 20 GB on the secondary.
For more information, please refer to -> 4.3 Use secondary site for DEV/QA System
Regards,
Ning
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Hi Ning,
Thanks for your replay..
As of now secondary one DR is configured, and its not possible to set any parameters through studio.
Then how to set them.
Also my actually primary prd instances size in 350 GB and 230 GB, is it OK to set the global allocation limit parameter to 64GB for both ....if so where to set from OS level.
Further where to find the row store size...?
Also let me know can we reduced the already allocated memory if needed in that development and quality instances.
Regards,
Vikram
Hi Vikram,
On secondary, directly edit the .ini file and adjust parameter.
For parameter locations, please refer to note 2186744 – FAQ: SAP HANA Parameters -> 3. Where can the configured SAP HANA parameters be found?.
In order to make sure that changes to online parameters are taken into account, you can force a reconfiguration using the following command:
hdbnsutil -reconfig
The row store size can be determined with this SQL statement which is already mentioned in the above document:
select host,round(sum(page_size*USED_BLOCK_COUNT)/1024/1024/1024,2) as "RowStore Size GB" from m_data_volume_page_statistics where page_sizeclass = '16k-RowStore' group by host;
Regards,
Ning
HI Ning,
Actually primary prd instances size in 350 GB and 230 GB, is it OK to set the global allocation limit parameter to 64GB for both secoundry PRD instances. (lesser value)
Also let me know can we reduced the already allocated memory if needed in that development and quality instances as the peak usage is less...
Allocated Peak used memory
DEV1 - 125G 75G
QAS1 - 275G 200G
DEV2 - 125G 75G
QAS2 - 175G 110G
Regards,
Vikram
Hi Ning,
Thanks for your information.
Let me know, if we takeover from primary to secoundry is it necessary to revert the preload_column_tables parameter from false to true.
Further we have builded another DR that is 2nd one (FAR). Is it same configuration as between primary and secoundry or any new settings needed.
Regards,
Vikram
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