Tuesday, November 25, 2014

RAC -- Preparing for the installation -- requests

RAC installation is a complex process which consists of several sub processes.
Preparing for RAC is the starting point among these processes.
In preparing phase, we as Database Administrators,RAC Admins deliver our system requirements to the client, we deliver our requirements by explaining the RAC and the related system concepts briefly.
Following is a system requirements paper delivered by me.. It was written pretty quickly and delivered after a RAC pre-install meeting with the client. It also contains the brief explaination about the migration process.
RAC system mentioned in the paper was supposed to be 11gR2 Linux RAC consisting of two nodes..

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RAC nodes will be Oracle Linux 6.5 64 bit, so Oracle Linux 6.5 iso file should be there for us.. It should be burned to DVD or mounted to the servers using ILOM/ILOM/etc. as Image file to before the installation.

After OS installation, Oracle Grid and Rdbms software installations will be done.
There will be 2 Diskgroups, DATA and RECO and the system will be ready for migration at this point.

RMAN, and rconfig will be used for the migration.. (Rman convert option + rconfig together will be used for Windows Single to Linux RAC migration process here)

The whole process will be 3-4 days.

A diagrammatic explaination of Oracle RAC:

The disks which will be presented by SAN should be in form of 8 lun( For ex:  rather than having 1x 1600 gb , we prefer  8x200 gb luns) We want 8 luns because the environment has multipath with 2 active paths, thus we prefer active path *4 luns for ASM. Disks should be aligned for ASM use.. 

In network side, te ip addresses and hostname should be ready before the installation day
Firewalls should be configured properly for RAC public ips and vips for client-applicaiton-database communication.

Network Requirements:

Public IPs , Private IPs, Virtual IP's ve SCAN IPs:

In both of the nodes:

We'll have 1 public , 1 private and 1 virtual ip addresses.
We'll have 3 Scan ip addresses and one scan hostnsame defined for these 3 ip addresses.. The scan ip and hostnames will be only on DNS.. A DNS with round robin capability.
We'll use bonding in Linux tier both for private and public interfaces.. So Network configuration, cabling and switch configuration should be done accordingly.

An Example Configuration:

Note: Public IPs, Virtual IPs and Scan s must be on the same subnet.
Node 1:

Public hostname :osrvdb01, public ip: 10.35.120.xx /255.255.255.0 --configured on the server before the installation, in DNS also..
Private hostname: osrvdb01-priv , private ip : 192.168.10.x /255.255.255.0 --configured on the server before the installation in its own subnet .NO Dns configuration.
Virtual hostname : osrv01-vip, virtual ip: 10.35.120.yy /255.255.255.0 --configured on DNS before the installation.


Node 2:

Public hostname :osrvdb02, public ip: 10.35.120.zz /255.255.255.0 --configured on the server before the installation, in DNS also..
Private hostname: osrvdb02-priv , private ip : 192.168.10.x /255.255.255.0 --configured on the server before the installation in its own subnet .NO Dns configuration.
Virtual hostname : osrv01-vip, virtual ip: 10.35.120.tt /255.255.255. --configured on DNS before the installation.

--once the cabling will be done, we ll configure the network interfaces and bonding in the linux tier.
Bonding will be active-backup.. It can be active-active load balanced if requested to be so.


Additionally;

3 scan entry defined in DNS:

erm-scan : 10.35.120.aa /255.255.255.0 --should be configured on DNS before the installation.
erm-scan : 10.35.120.bb /255.255.255.0 --should be configured on DNS before the installation.
erm-scan : 10.35.120.cc /255.255.255.0 --should be configured on DNS before the installation.

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