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Here are the list of Oracle Support ID's for Oracle Apps DBAs, I do refer regularly. Moreover, these are very informative. So, I thought of sharing those note ids here with you. Note : You have to have an account in Oracle Support to access id's. Points of Interest Installation Real Application Cluster (RAC) AD Utility Cloning Patching Upgrades Printer Performance Others Oracle Application DBA Field Guide

Oracle 11.2 fully supports continuing to use non-11.2 databases on a cluster that has been upgraded to 11.2. However, you should be aware that the Oracle 11.2.0.1 base release contained a number of problems that could affect users with a 10.2 database. Known problem with brand new installations of Grid Infrastructure 11.2 and pre-11.2 RDBMS instances is related to node pinning. During the upgrade, the nodes containing 10.2 RDBMS software will be pinned, allowing pre-11.2 databases to run on them. Important aspect is with Non-upgraded clusters are not automatically pinned, which causes problems with emca and dbca when executed from the pre-11.2 Oracle homes. You should use the utilities from the $GRID_HOME to manage resources provided by the same Oracle home. Similarly, when managing pre-11.2 resources, you can use the commands from their respective homes. This is a golden rule to remember You can find more information about problems with 10.2 databases and 11.2 Grid Infras...

The Single Client Access Name is a new feature that simplifies acces to a cluster database. In versions proir to Oracle RDBMS 11.2, an entry in the tnsnames.ora file for a n-npde RAC database always referenced all nodes in the address_list section. From Oracle RDBMS 11.2 the RAC databases can be covered with the SCAN method. A SCAN method is a hostname based method on 1 - 3 virtual IP-addresses based in the DNS of the organisation. The SCAN method solved an TNS ENTRY editing issue in the TNSNAMES.ORA, on actions of adding and removing nodes from the cluster. SCAN method makes my life easier in managing the Oracle sqlnet configurations for the Oracle cluster databases.

Important is that the storage devices operational, mounted and stamped as ASM device to the machine. Using Management Volume (ACFS) the compatibility level must be at least 11.2. on diskgroup level. See below the created statements from the diskgroups inside the ASM. De disksgroups are created with the compatible.* -> 11.2 . The diskgroup that will be used for ACFS is the diskgroup “ DG_DISK11G_01 ” Steps involved to use ACFS Create Diskgroups Load ACFS Drivers Create Filesystem for ACFS Volume Device Mount ACFS Filesystem ASMCA validation of ACFS Filesystem Automatic startup ACFS Mount Device Oracle ACFS Mount Registry

Oracle Deferred Segment Creation new feature in Oracle Database 11g Release 2. Creating a non-partitioned heap-organized table in a locally managed tablespace, the table segment creation is deferred until the first row is inserted. In addition, creation of segments is deferred for any LOB columns of the table, any indexes created implicitly as part of table creation, and any indexes subsequently explicitly created on the table.

New in Oracle 11g, you can place a table in read-only mode with the ALTER TABLE...READ ONLY statement, and return it to read/write mode with the ALTER TABLE...READ WRITE statement. An example of a table for which read-only mode makes sense is a configuration table. If your application contains configuration tables that are not modified after installation and that must not be modified by users, your application installation scripts can place these tables in read-only mode. The table is in read-only mode, operations that attempt to modify table data are disallowed.

Data Guard redo configuration asynchronous mode, the Log Network Server (LNS) process will attemp to read redo directly from the log buffer. If the redo to be sent is not found in the log buffer, then the LNS process will go to the Online Redo Log (ORL) to retrieve it. Size the log buffer so that LNS is always able to find the redo that is needs to send within the log buffer. The log buffer hit ratio is tracked in the view x$logbuf_readhist . A low hit ratio indicates that the LNS is frequently reading from the ORL instead of the log buffer. If there are periods when redo transport is coming close, but is not quite keeping pace with your redo generation rate, consider increasing the log buffer size in Data Guard 11g to achieve a favorable hit ratio.