Linux Virtual Server - LVS Cluster - NAT

Posted on 2011-02-19
Medium Priority
Last Modified: 2013-11-08
Hello Everyone:

We have used F5 Networks load balancing solutions for some time within our company.  Two years ago, we decided to implement our own lvs cluster of http servers.  Everything is working fairly well, nodes are appropriately load balanced according to lvs-nat scheduling.

Today, I was reviewing normal system activities, inspecting routing configurations and looking at traffic on each of the real servers.  I observed the following and was wondering if it was normal on lvs clusters.  

This information was captured from the node       ESTABLISHED  268m   0 B/s

It seems like the kernel, is allowing connections to stay in the ESTABLISHED state for entirely too long.  Ideas on what to check?  I've watched the TCP session off and on for the last hour or so and I have not observed any traffic through the ESTABLISHED connection.  Why isn't it terminating???  Not too sure on what direction to look on this one.  
Question by:christopherdonahue
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Author Comment

ID: 34936852
Increased to 500 points on this issue.
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Expert Comment

by:Duncan Roe
ID: 34946348
If the connection is ESTABLISHED, neither end has closed. That's between applications. There is not normally any time out when this happens.

Author Comment

ID: 35073673
Interesting, any ideas why the connection would be held open but, while watching activity on the connection, nothing is being transferred?

LVL 35

Accepted Solution

Duncan Roe earned 2000 total points
ID: 35074128
It's down to the application software. Not serious usually. It may even be intended to work that way

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