About RAC VIP

If a node fails, then the node's VIP fails over to another node on which the VIP cannot
Accept connections.

What does this sentence mean? If the node fails, the VIP address of the node will be switched to another node where the VIP address cannot be connected. What is the meaning of switching? The following replies make sense:

Improve user experience.
If VIP is not used, the user must endure tcp timeout for a long time.
After VIP is used, the ora error will be reported when the user connects to the crash instance.
The TAF configuration on the client will try the next node.

This is also consistent with the document. I understand that there are three levels. First, the server implements VIP switching and returns a connection error to the client immediately. Secondly, although the client accepts the error, however, through the TAF configuration, the next node will be attempted. Finally, for applications, because the service registered through the client connects to the server, the "transparent application failure switchover (TAF)" will be truly achieved )".

What do you think? The following is a problem with TAF configuration.

 

Let's take a look at what TOM says:

 

Dear Tom,

In addition to Private & Public IP address, 10g RAC requires VIP (Virtual IP ).
Document did not explain much about VIP.

Cocould you please explain what is the purpose on this extra IP address (VIP is
Not required in 9i ).

Thanks in advance

Followup:
View support note <Note: 264847.1>

And from <Note: 220970.1>

Its all about availability of the application.

When a node fails, the VIP associated with it is supposed to be automatically
Failed over to some other node. When this occurs, two things happen. (1) the new
Node re-arps the world indicating a new MAC address for the address.
Directly connected clients, this usually causes them to see errors on their
Connections to the old address; (2) Subsequent packets sent to the VIP go to
New node, which will send error RST packets back to the clients. This results in
The clients getting errors immediately.

This means that when the client issues SQL to the node that is now down, or
Traverses the address list while connecting, rather than waiting on a very long
TCP/IP time-out (~ 10 minutes), the client has es a TCP reset. In the case
SQL, this is ORA-3113. In the case of connect, the next address in tnsnames is
Used.

Without using VIPs, clients connected to a node that died will often wait a 10
Minute TCP timeout period before getting an error.

As a result, you don't really have a good HA solution without using VIPs