Description

To confirm heartbeat connectivity between two nodes in a Veritas Cluster Server (VCS), use the following llttest command line tool to send and receive messages between the two nodes. 

Example:
This VCS cluster contains two nodes: node 0 and node 1. Here, node 1 will be the sender and node 0 will be the receiver.

1. Run lltstat -nvv to determine the host number of each node.

2. Open a command prompt on each server and start llttest using the following:

llttest -p 4 -v

Here, llttest is being started using port 4. This needs to be done on both nodes. 
 

3. On node 1, type t -n  0 -c 100.

Here, we are transmitting 100 count messages to node 0 ( t = transmit, -n = node to send to, -c = Number of count msgs to send).

4. On node 0, type r -c 100.

Here we are receiving 100 count messages from node 1 ( r = receive,  -c = Number of count msgs to receive).

5. On the receiving node you should receive a message similar to this:
"receiving 100 messages"

If you receive a similar message, this confirms that the message was sent between node 1 and node 0.

6. Now, try sending a message from node 0, and receiving from node 1. On node 0, type t -n 1 -c 100.

7. On node 1, type r -c 100. If you receive the message, and the number of messages sent through, then the message from node 0 to node 1 was successful. From this you can conclude that LLT communication between the two nodes, node 0 and node 1 is working.