Who is the Master Node in my Oracle Cluster?
I got this question during my present course Oracle Grid Infrastructure 11g: Manage Clusterware and ASM while we discussed backup of the OCR. That backup is done by the OCR Master, which can be any node in the cluster. It is therefore recommended to configure the backup location to a shared folder that is accessible from all cluster nodes. But back to the question – here is how to find the OCR Master of the Oracle Cluster:
[grid@host01 ~]$ cat /u01/app/11.2.0/grid/log/host01/crsd/crsd.log | grep -i 'ocr master' 2013-09-17 07:49:44.237: [ OCRMAS][3014282128]th_master:12: I AM THE NEW OCR MASTER at incar 1. Node Number 1 2013-09-17 07:53:00.305: [ OCRMAS][3009534864]th_master:12: I AM THE NEW OCR MASTER at incar 1. Node Number 1 2013-09-17 12:19:21.414: [ OCRMAS][3009604496]th_master: NEW OCR MASTER IS 2 [grid@host01 ~]$ olsnodes -n host01 1 host02 2 host03 3
(GRID_HOME and local hostname) The CRSD (Cluster Registry Service Demon) is the one who deals with the OCR, which is why I search through this log file.
The Master Node of the Cluster is the one who will become the only surviving node if the interconnect fails completely. It is also the node who will pass the time to the other nodes in the absence of NTP via CTSSD (Cluster Time Synchronization Service Demon). I suppose it is always the same as the OCR Master, but just to be on the safe side, you can check that this way:
[grid@host01 ~]$ cat /u01/app/11.2.0/grid/log/host01/cssd/ocssd.log | grep -i 'master node' 2013-09-17 07:48:53.541: [ CSSD][3004672912]clssgmCMReconfig: reconfiguration successful, incarnation 274866533 with 1 nodes, local node number 1, master node number 1 2013-09-17 07:49:47.427: [ CSSD][2990480272]clssgmCMReconfig: reconfiguration successful, incarnation 274866534 with 1 nodes, local node number 1, master node number 1 2013-09-17 07:52:27.595: [ CSSD][2989472656]clssgmCMReconfig: reconfiguration successful, incarnation 274866536 with 1 nodes, local node number 1, master node number 1 2013-09-17 07:59:20.783: [ CSSD][2989472656]clssgmCMReconfig: reconfiguration successful, incarnation 274866537 with 2 nodes, local node number 1, master node number 1 2013-09-17 11:34:59.157: [ CSSD][2989472656]clssgmCMReconfig: reconfiguration successful, incarnation 274866538 with 3 nodes, local node number 1, master node number 1 2013-09-17 12:18:48.885: [ CSSD][2992602000]clssgmCMReconfig: reconfiguration successful, incarnation 274866540 with 3 nodes, local node number 1, master node number 2 2013-09-17 12:22:52.660: [ CSSD][2992602000]clssgmCMReconfig: reconfiguration successful, incarnation 274866541 with 2 nodes, local node number 1, master node number 2 2013-09-17 12:23:32.836: [ CSSD][2992602000]clssgmCMReconfig: reconfiguration successful, incarnation 274866542 with 3 nodes, local node number 1, master node number 2 2013-09-17 12:26:29.474: [ CSSD][3016432528]clssgmCMReconfig: reconfiguration successful, incarnation 274866543 with 3 nodes, local node number 1, master node number 2 2013-09-17 12:28:42.960: [ CSSD][2987871120]clssgmCMReconfig: reconfiguration successful, incarnation 274866544 with 3 nodes, local node number 1, master node number 2
The CSSD (Cluster Synchronization Service Demon) is the one who deals with the Voting File that is used to determine which nodes must reboot and which nodes will survive in case of a problem with the Interconnect. Therefore, I search through its log file to determine the Master of the Cluster.
The question comes up quite often, so this little post will be handy to point to in the future. Hope you find it useful as well 🙂
Automatic Creation of Standby Logs with RMAN DUPLICATE?
Just a brief information for you out there who are about to create a Data Guard Configuration. You will want to have Standby Redo Logs (SRLs) on the Standby Database. Our (otherwise very good) Online Documentation says „RMAN automatically creates the standby redo log files on the standby database.“ That is true, but only if you created them before on the Primary! That was already the case with 11g and it still is with 12c, which I have just tested. Here’s the outcome after the RMAN DUPLICATE without SRLs on the Primary, checking the alert log of the Standby:
Use the following SQL commands on the standby database to create standby redo logfiles that match the primary database: ALTER DATABASE ADD STANDBY LOGFILE 'srl1.f' SIZE 104857600; ALTER DATABASE ADD STANDBY LOGFILE 'srl2.f' SIZE 104857600; ALTER DATABASE ADD STANDBY LOGFILE 'srl3.f' SIZE 104857600;
Confirmation with SQL*Plus:
[oracle@uhesse]$ sqlplus sys/oracle@physt as sysdba
SQL*Plus: Release 12.1.0.1.0 Production on Fri Sep 6 09:06:08 2013
Copyright (c) 1982, 2013, Oracle. All rights reserved.
Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options
SQL> select * from v$standby_log;
no rows selected
Conclusion: Don’t believe it (even if it is the Documentation), test it!“ 🙂
Oracle University Instructors at DOAG 2013: The Program
My dear colleague Joel Goodman and me will present at the DOAG (German Oracle User Group) Annual Conference 2013; I’m already excited about it 🙂
Apart from seeing presentations by top-notch Oracle Experts, I’m also looking forward to meet people in person that I know already from social media activity. The complete program is online here. My personal choice of presentations (a pity that I can’t see all) is
Day 1 (19-NOV)
DB Time-based Oracle Performance Tuning: Theory and Practice by Graham Wood, Oracle
Instant DB Cloning by Kyle Hailey, Delphix
Session Keynote: Best Practices for Data Availability and Disaster Protection by Larry Carpenter, Oracle
Upgrading to Oracle 12c by Julian Dontcheff, Accenture
Keynote by Andy Mendelssohn, Oracle
RAC Global Resource Management Concepts by Joel Goodman, Oracle
Why and How You Should Be Using Policy-Managed Oracle RAC Databases by Mark Scardina, Oracle
Thinking Clearly about Performance by Cary Millsap, Method R Corporation
Day 2 (20-NOV)
Materialized Views & Partition Change Tracking, my rifle, pony and me
Arbeiten mit Pluggable Databases (Oracle Multitenant) in der Praxis by Mike Dietrich, Oracle
Exadata Database Machine – Die Konsolidierungsplattform by Malthe Griesel, Paragon Data GmbH
Statistics Gathering 101 by Wolfgang Breitling, Centrex Consulting Corporation
Achieving Availability and Scalability with Oracle 12c Flex Clusters by Kai Yu, Dell Inc
Oracle Real Application Clusters (RAC) 12c Best Practices by Markus Michalewicz, Oracle
Neue 12c Features für Datawarehouse by Frank Schneede, Oracle
Day 3 (21-NOV)
Best of Oracle Security 2013 by Alexander Kornbrust, Red Database Security GmbH
A Presentation of Sorts by Julian Dyke
Session Keynote: Simplify Consolidation with Oracle Database 12c by Patrick Wheeler, Oracle
Experten-Panel: Dataguard hosted by Matthias Mann, Christian Trieb
Instrumenting Oracle CPU activity: The Missing Link by Craig Shallahamer, OraPub
Query Optimizer 12c Was ist neu? by Christian Antognini, Trivadis AG
Oracle Partitioning fuer Einsteiger by Hermann Baer, Oracle
If you plan to come to this event, this hotel is closest. Make your reservations early. Hope to see YOU at the conference 🙂
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