Category Archives: Oracle DBA Practice

ORA-27125: unable to create shared memory segment Linux-x86_64 Error: 28: No space left on device

When try to start up an Oracle database, the below errors occur: ORA-27125: unable to create shared memory segment Linux-x86_64 Error: 28: No space left on device Additional information: 3773 Additional information: 3221225472 CAUSE Kernel parameter kernel.shmall is not set properly. … Continue reading

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How to Relink Oracle 12CR2 Grid Infrastrure ( GI ) Binary

1)Change ownership of some root owned files like extjobO and jssuO, etc, because the relink script will be run as “grid’ user to change the file permissions. Otherwise, the relink will fail from the below commands in scripts: … .. . chmod … Continue reading

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Error in invoking target ‘agent nmhs’ of makefile

Below errors occurred while install 11.2.0.4 on Linux 7.4.  when relink the binary, the same error will be reported as well. INFO: collect2: error: ld returned 1 exit status INFO: make[1]: INFO: *** [/u01/app/oracle/product/11.2.0/dbhome_1/sysman/lib/emdctl] Error 1 INFO: make[1]: Leaving directory … Continue reading

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How to Remove Oracle RAC Software

1)Check to make sure there is no database still using this ORACLE_HOME: $ srvctl status database -thishome 2) De-install the binary of Oracle RAC HOME cleanly by: $ /u01/app/oracle/product/12.1.0/dbhome_1/deinstall/deinstall — logs: Checking for required files and bootstrapping … Please wait … Continue reading

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SRVCTL Useful Commands

1)To check status of databases that are configured in this Oracle Home. $ srvctl status database -thishome 2) To check status of databases that are of the same Oracle product version. $ srvctl status database -thisversion

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Asmcmd Pwcopy With PRCD-1163 PRCR-1071 CRS-0245 ASMCMD-9453 Errors

After standby database rebuilt, and trying to copy database password file from primary to standby ASM disk, the below errors occurred: ASMCMD> pwcopy –dbuniquename RACTEST ‘/tmp/orapwractest’ ‘+DATA/RACTEST/orapwractest’ copying /tmp/orapwractest -> +DATA/RACTEST/orapwractest PRCD-1163 : Failed to modify database RACTEST PRCR-1071 : … Continue reading

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How to Migrate SQL Plan Baselines Between Oracle Databases

After database upgrading / Patching, or database is migrated onto new infrastructure, it is common to see database performance is degrading due to SOL execution plans changed. What we can do is by creating  SQL plan baselines from old database, … Continue reading

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How to Update Opatch Utility of GI Home

Due to GI_HOME restricted access, you might get below errors when you extract opatch utility to GI_HOME: checkdir error:  cannot create /u01/app/12.2.0.1/grid/OPatch                  Permission denied                  unable to process OPatch/config/opatch.properties. Below is one of the appropriate way for extracting opatch … Continue reading

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Query on v$asm_diskgroup Hangs

Due to underneath SAN LUN issue, after manually dismounting problem disk group, the queries on v$asm_* views hang forever. 1)  Check blacking sessions, and find blocking session is SID=426, and the final blocking session us SID=392. SQL> select SID,LAST_CALL_ET,EVENT,BLOCKING_SESSION,FINAL_BLOCKING_SESSION from … Continue reading

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How to Prevent ASM Diskgroup Automatic Mount

1) To disable certain ASM Diskgroup automatic mount on all RAC nodes, run below command as grid user: $ srvctl disable diskgroup -diskgroup testdg 2) To disable certain ASM Diskgroup automatic mount on specific RAC node, run below command as … Continue reading

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