Symptom
There is no HANA System Replication enabled (see below <hdbnsutil -sr_state>), but there are a large number of log segments (from indexserver) in RetainedFree status which fill up /hana/log volume.
<hdbnsutil -sr_state>
--------------------------------------
System Replication State
~~~~~~~~~~~~~~~~~~~~~~~~
online: true
mode: none
done.
--------------------------------------
<log status>
--------------------------------------
> for i in $(find -L /hana/log/${DIR_INSTANCE:9:3} -name 'hdb*' -type d) ; do echo $i ; hdblogdiag seglist $i | grep -oP 'Formatting|Preallocated|Writing|Closed|Truncated|BackedUp|RetainedFree|\bFree\b' | sort | uniq -c ; done
/hana/log/SID/mnt00001/hdb00001
1 Free
1 Writing
/hana/log/SID/mnt00001/hdb00002.00003
589 RetainedFree
1 Writing
...
--------------------------------------
global.ini from tenant DB (/usr/sap/<SID>/SYS/global/hdb/custom/config/DB_<tenant DB>) contains the same or similar entries as below.
--------------------------------------
[system_replication]
mode = primary
actual_mode = primary
...
enable_log_retention = on
...
--------------------------------------
global.ini from SYSTEMDB (/usr/sap/<SID>/SYS/global/hdb/custom/config) may also contain some HSR related parameters as below.
--------------------------------------
[system_replication]
timetravel_logreplay_mode = auto
operation_mode = logreplay
replication_port_offset = 100
...
[system_replication_hostname_resolution]
...
--------------------------------------
indexserver trace may contain the same or similar messages like below.
----------------------------
[22860]{-1}[-1/-1] 2024-05-06 14:31:07.505552 i Logger LoggerImpl.cpp(00534) : Initial Log Retention: On
...
Line 34737: [22409]\{100162\}[21/108253169] 2024-05-06 16:39:12.413958 i Logger LoggerImpl.cpp(01592) : Try to free RETAINED_FREE segments, logshipping_max_retention_size=109,943,193,600byte
Line 35157: [22346]\{100162\}[21/108253230] 2024-05-06 16:42:11.968918 i Logger LoggerImpl.cpp(01592) : Try to free RETAINED_FREE segments, logshipping_max_retention_size=1,098,907,648byte
Line 35855: [56842]{-1}[-1/-1] 2024-05-06 16:57:19.617017 i Logger (00534) : Initial Log Retention: On
----------------------------
or
----------------------------
[48344]{-1}[-1/-1] 2024-05-17 15:37:48.875881 i PersistenceManag PersistenceManagerImpl.cpp(05508) : Configure System Replication Primary in Persistence Manager
[48344]{-1}[-1/-1] 2024-05-17 15:37:48.876833 i sr_dataaccess DisasterRecoveryPrimaryImpl.cpp(02426) : Secondary with siteId=0 () opMode=invalid operation mode is newly registered
----------------------------
"Image/data in this KBA is from SAP internal systems, sample data, or demo systems. Any resemblance to real data is purely coincidental."
Read more...
Environment
SAP HANA, platform edition 2.0
Product
Keywords
HANA, log, RetainedFree, Free, system replication, HSR, non-HSR, Initial Log Retention: On, enable_log_retention , KBA , HAN-DB-HA , SAP HANA High Availability (System Replication, DR, etc.) , Problem
About this page
This is a preview of a SAP Knowledge Base Article. Click more to access the full version on SAP for Me (Login required).Search for additional results
Visit SAP Support Portal's SAP Notes and KBA Search.