How Oracle RAC Environments Adjust system time

Tuning system time is not a trivial thing for a RAC environment, and Oracle is likely to reboot one of the nodes to ensure consistency between nodes.

The test found that if the system time is adjusted forward, no matter how long the adjustment will not cause the system to restart. However, if the system time is adjusted backwards, it will cause the whole node to reboot.

Even if you close the database, the tuning time will still restart the node.

The correct approach is to first shut down the database and cluster environment, and then modify the system time, in order to avoid conflicts in the database, it is best to wait for the current time to exceed the modified system time before starting the cluster environment and the RAC database:

# date

Tue Aug 4 17:51:44 CST 2009

# su-oracle

Sun Microsystems Inc. SunOS 5.10 Generic January 2005

You have mail.

$ bash

bash-3.00$ Sqlplus/as SYSDBA

Sql*plus:release 10.2.0.3.0-production on Tuesday August 4 17:51:59 2009

Copyright (c) 1982, 2006, Oracle. All Rights Reserved.

Connect to:

Oracle database10genterprise Edition Release 10.2.0.3.0-64bit Production

With the partitioning, real application clusters, OLAP and Data Mining options

sql> shutdown Immediate

The database has been closed.

The database has been unloaded.

The Oracle routine has been closed.

Sql> exit

From Oracle database10genterprise Edition release 10.2.0.3.0-64bit Production

With the partitioning, real application clusters, OLAP and Data Mining options disconnected

bash-3.00$ Lsnrctl Stop

Lsnrctl for Solaris:version 10.2.0.3.0-production on April-August-2009 17:54:41

Copyright (c) 1991, 2006, Oracle. All rights reserved.

Connecting to (Address= (PROTOCOL=TCP) (host=) (port=1521))

Command execution succeeded

bash-3.00$ exit

Exit

$ exit

# date

Tue Aug 4 17:54:51 CST 2009

#/etc/init.d/init.crs Stop

Shutting down Oracle Cluster Ready Services (CRS):

Aug 4 17:54:57.422 | INF | Daemon shutting down

Stopping resources.

Successfully stopped CRS resources

Stopping CSSD.

Shutting down CSS daemon.

Shutdown request successfully issued.

Shutdown has begun. The daemons should exit soon.

# date

Tue Aug 4 17:55:02 CST 2009

# date 080417472009.20

Tue Aug 4 17:47:20 CST 2009

# date

Tue Aug 4 17:59:18 CST 2009

#/etc/init.d/init.crs Start

Startup would be queued to init within seconds.

# Ps-ef|grep Ora

Oracle 18590 1 0 17:55:01? 0:00 sh-c sh-c ' Ulimit-c Unlimited; Cd/opt/oracle/product/10.2/crs/log/ahrac1/ev

Oracle 24249 1 0 18:01:03? 0:00 oracletradedb1 (description= (Local=yes) (address= (PROTOCOL=BEQ))

Root 18636 1 0 17:55:01? 0:01/opt/oracle/product/10.2/crs/bin/crsd.bin reboot

Oracle 24454 1 0 18:01:09? 0:00 ORA_Q001_TRADEDB1

Oracle 23386 1 0 18:00:34? 0:00 ORA_PMON_TRADEDB1

Oracle 22101 21913 0 17:59:52? 0:00 sh-c/bin/sh-c ' Ulimit-c Unlimited; Cd/opt/oracle/product/10.2/crs/log/ahra

Oracle 23445 1 0 18:00:35? 0:00 ORA_RECO_TRADEDB1

Oracle 24450 1 0 18:01:09? 0:00 oracletradedb1 (description= (Local=yes) (address= (PROTOCOL=BEQ))

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