DB2 - Problem description
Problem IT23814 | Status: Closed |
HADR LOG GAP ON AUXILARY STANDBY INCREASES SIGNFICANTLY WHILE ONLINE BACKUP IS RUNNING. | |
product: | |
DB2 FOR LUW / DB2FORLUW / A50 - DB2 | |
Problem description: | |
In databases with extremely high transaction log volume workloads, and which are configured for HADR with one or more AUXILIARY Standby databases, the HADR_LOG_GAP between the Primary database and the Auxiliary Standby database(s) may increase significantly during the INCLUDE LOGS phase of the Online Backup. The HADR_LOG_GAP will recover to normal upon completion of the Online Backup. | |
Problem Summary: | |
**************************************************************** * USERS AFFECTED: * * All * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Upgrade to release inclusive of this fix. Refer to sysroute * * APAR. * **************************************************************** | |
Local Fix: | |
Upgrading to the Fix Pack inclusive of this APAR fix may provide relief. Also, utilizing the online Backup EXCLUDE LOGS option will resolve the symptom. When the online Backup EXCLUDE LOGS option is used, users will need to self manage and save the log files required to restore this online backup image at a later date. The following instructions may help you assess if this is a viable alternative in your environment: 1. Perform the online Backup using the EXCLUDE LOGS option. 2. Upon completion of the online backup, you can determine the span of logs that would need to be saved in order to restore this backup image to a consistent point in time, by querying the DB_HISTORY administrative view: (Note in my query below, I return only the most recent backup operation by filtering OPERATION= 'B' and ordering by START_TIME descending and using the FETCH FIRST 1 ROWS clause). $ db2 select "OPERATION, substr(BACKUP_ID,1,20) as BACKUP_ID, START_TIME, substr(FIRSTLOG,1,20) as FIRSTLOG, substr(LASTLOG,1,20) as LASTLOG from SYSIBMADM.DB_HISTORY where OPERATION='B' order by START_TIME desc fetch first 1 rows only" OPERATION BACKUP_ID START_TIME FIRSTLOG LASTLOG --------- -------------------- -------------- -------------------- -------------------- B - 20180221153249 S0000106.LOG S0000108.LOG 1 record(s) selected. 3. Copy this span of log files for safe keeping wherever the backup image is stored. Note, if you retain archived log files for a period of time that aligns with the oldest possible restore you may need, then you may not actually need to save the log files with the backup images, since you will already have them in the the archive log path. 4. When restoring a backup image at a later date, the path to these log files can be provided by using the OVERFLOW LOG PATH option. You can either specify the path of your log archive location (as I've done below), or the path to wherever you saved the log files with the backup image files. You can perform a rollforward to end-of-backup (as I've done below), or end-of-logs if you prefer. $ db2 restore db HADR105 taken at 20180221153249 DB20000I The RESTORE DATABASE command completed successfully. $ db2 "rollforward db hadr105 to end of backup overflow log path (/home/dsciaraf/mylogarchpath/dsciaraf/HADR105/NODE0000/LOGSTREA M0000/C0000000/)" Rollforward Status Input database alias = hadr105 Number of members have returned status = 1 Member ID = 0 Rollforward status = DB working Next log file to be read = S0000109.LOG Log files processed = S0000106.LOG - S0000108.LOG Last committed transaction = 2018-02-21-20.33.03.000000 UTC DB20000I The ROLLFORWARD command completed successfully. | |
Solution | |
Workaround | |
not known / see Local fix | |
BUG-Tracking | |
forerunner : follow-up : IT24520 | |
Timestamps | |
Date - problem reported : Date - problem closed : Date - last modified : | 23.01.2018 23.03.2018 23.03.2018 |
Problem solved at the following versions (IBM BugInfos) | |
Problem solved according to the fixlist(s) of the following version(s) |