RAC Implementation

Hi guyz i would like to share some RAC implementation points

 

First OS should be installed in our nodes, this is will be taken care by the OS Team.

 

For RAC setup, Oracle has provided Clusterware, Oracle Clusterware is the cross platform cluster software required to run the Real Application Clusters (RAC) option for Oracle Database. It provides the basic clustering services at the operating system level that enable Oracle software to run in clustering mode.

 

Important files of Clusterware:-

 

• OCR
• VOTING DISK/VOTING FILE
• Two RAW disk  for OCR and Voting file
• OCFS to place OCR/Voting disk(optional)
• ASM [it is still not available, because ASM binaries comes along with oracle binaries. we didnt' install Oracle yet]
• Oracle Home [Oracle binaries will be stored]

If we need to create a database, storage area should be in place, so that we need to start ASM instance in all the nodes.

In Oracle 11gR2 we can place OCR & Voting File in ASM Diskgroup since ASM binaries comes bundled along with Clusterware binaries that is grid infrastructure services for cluster

Network configuration are done by the network team: Configuring Public IP, Private IP and Virtual IP.

 

Configuration of SSH: 

Whenever we create oracle users in all the participating nodes the groupid, userid should be identical in all the nodes. if we create group or users OS(Operating system) will recognize based on the id. otherwise the cluster installation will fail. Using RSA/DSA(Algorithm we are going to configure SSH from the /home/oracle/.ssh[incidentally the user's home directory]. Once the SSH is configured the password is encrypted using 128 bit encryption algorithm

11gR2----> click to configure SSH automatically(RSA/DSA) copy the public keys from the nodes and paste it or make it available in all the participating nodes.

eg: 2 nodes===>4 public keys

High Level RAC Implementation:

1. Install hte same version of OS in all the participating nodes. 
2. Create the required number of groups and users accounts in all the cluster nodes(groupid and userid should be identical in all the nodes)
3. Create the directory structures for CRS_HOME and DB_HOME in all the cluster nodes
4. Configure Kernel parameters & set the semaphore settings as per oracle  document.
5. set shell limits for oracle user account
6. edit /etc/hosts and specify the public/private ip & Virtual IP for all the cluster nodes
7. Establish trust relationship and user equivalence by configuring SSH
8. create the required number of partitions in the shared storage for OCR, Voting File and ASM Diskgroups
9. if Implementing RAC in Linux using ocfs2 and ASM interface download the corresponding RPM based on the kernel version of the node's OS.
10. ensure the date and time are close as possible in all the cluster nodes.

All the above steps will be configured by the OS Admin and Network Admin with the co-ordination of Oracle DBA. Here starts the work of DBA

1. Install Clusterware in the first node and at the end of the installation if cluvfy fails it is considered as a bug in 10g. Workaround according to the oracle metalink.
2. configure listener
3. configure ASM instance and create diskgroups needed for it
4. Create RAC database in the shared storage area.