Oracle RAC 11gR2 Client Side TAF.

TYPE: TAF supports three types of failover types

1.SESSION failover - If a user's connection is lost, SESSION failover establishes a new session 

automatically created for the user on the backup node. This type of failover does not attempt 

to recover selects. This failover is ideal for OLTP (online transaction processing) systems, 

where transactions are small.

2.SELECT failover – If the connection is lost, Oracle Net establishes a connection to another 

node and re-executes the SELECT statements with cursor positioned on the row on which it was 

positioned prior to the failover. This mode involves overhead on the client side and Oracle 

NET keeps track of SELECT statements. This approach is best for data warehouse systems, 

where the transactions are big and complex

3.NONE: This setting is the default and no failover functionality is provided. Use this setting to

 prevent failover.

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Oracle RAC 11gR2 ACFS Configuration & Snapshots.

On Oracle Version 11.2.0.1 ACFS is only supported on the following OS Platforms.

1) OL5 and RHEL5
2) Windows 2003 R1 (64-bit)
3) Windows 2003 R2 (64-bit)

Oracle ACFS Disk Space Usage.

1) Upto 64 million files in a file system.
2) 63 snapshots.
3) 64 Mounts on 32-bit systems.
4) 256 Mounts on 64-bit systems.

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Oracle RAC 11gR2 ASMCMD Commands.

Saving your ASM Spfile.


Check spfile location.

[root@rac1 bin]# su - grid
[grid@rac1 ~]$ echo $ORACLE_SID
+ASM1
[grid@rac1 ~]$ sqlplus / as sysasm

SQL*Plus: Release 11.2.0.1.0 Production on Sat Sep 22 00:46:33 2012

Copyright (c) 1982, 2009, Oracle.  All rights reserved.

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Oracle RAC 11gR2 Voting Disks & OCR Backups.

Voting Disks

In 11g release 2 you no longer have to take voting disks backup. In fact according 
to Oracle documentation restoration of voting disks that were copied using the 
"dd" or "cp" command may prevent your clusterware from starting up.

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Oracle RAC 11gR2 Clusterware and Database Administration.

Prior to 11gR2 "crs_stat -t" was used for checking the status of all the resources
But now "crsctl status resource -t" can be used in it's place.

I have a test two node RAC system on which i am going to demonstrate some of
the database and clusterware administration commands.

Here are some important notes from Oracle Docs on "SRVCTL" & "CRSCTL" utilities which are
going to be used in this article.

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How to configure VNC Server in RHEL5 ?

Install Vnc Server

[root@test ~]# yum install *vnc*


[root@test ~]# vncserver :1

You will require a password to access your desktops.

Password:
Verify:

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How to configure VNC Server in RHEL6 ?

Disable nm controlled network management.

vi /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE="eth0"
NM_CONTROLLED="no"
ONBOOT="no"
HWADDR=00:0C:29:AA:10:3D
TYPE=Ethernet
BOOTPROTO=none
IPADDR=192.168.1.30
PREFIX=24
GATEWAY=192.168.1.1
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=no

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