NIC alias in Rhel 7 oracle rac

[satish]

Hi erman,

Our OS RHEL 7.3
2 node rac 12.1.0.2

 
bond0 is configured with eth0 and eth1 for public NIC.What is the reason for additional bond0:1, bond0:2, bond0:3, bond0:4 in our environment.In what cases,they will go for it and what is the use.

Pls advice

Thank you

[ErmanArslansOracleBlog]

Those are virtual interfaces. The reason for using them differs according to the scenario..
For instance, we use them in RAC in order to be able get rid of the need for waiting the TCP timeout..
We failover the those virtual ones and respond in case of a network or node failure..
We response but the listeners of the remaining node/or nodes will not get the connection from that migrated ip address.
But we reply! no waiting for TCP timeout there.
So the client gets the reply (the errors) and continues with the next available ip addresses supported by the listener of the survived node or nodes..
So it depends.. Read some docs and you will see other scenarios for understanding the reason behind using these types of interfaces.

[satish]

Dear erman,

Any reference articles please

Thank you

[ErmanArslansOracleBlog]

It is an OS and network config required for RAC. So your OS admin will tell you why he made a virtual ip on bond.. But it will work.. You can put a vip on a normal interface or bond interface, it doesn't really matter.. The only thing that matter is that you meet the requirements of RAC.

So, these are configured on OS and you configure your RAC according to your needs.. You configure the RAC and use the relevant OS interfaces for your purpose.. So it depends on your cluster config. Check the cluster and see which component uses them? Check the local listeners, check the scan listener, see the ip addresses they listen and then you will understand..
 
We have SCAN ip addresses used by scan listeners, virtual ip addresses used by Local listeners and so on..

Here is a doc for taking a look to the VIP concept in Oracle ->

https://docs.oracle.com/database/121/RACAD/GUID-6C72F02D-BB43-4C56-9F46-244C8D6BB670.htm