Server unavailability

[Anon Anon]

Hi,

I have enabled availability monitoring for the servers in SA. For some time instant, it was showing "Server unavailable" in Super Agent but originally the server was reachable and there was no issue in server.

why is like that? what can be the issue?

Can anybody help me?

[Stuart Weenig]

When server availability is turned on for the server (and the app and the
collector), SA looks for data inactivity during a 5 minute period.
Specifically, it looks for no data coming from the server. If this is the
case, the collector will try a TCP connect to the server on the application
port. If this is successful, SA marks the 5 minute period as white,
meaning no data. If this test is unsuccessful, SA marks the 5 minute
period as red, indicating unavailable.

If your SA marked it as red, then the collector saw no data from the
server, so it did a TCP connection test. That failed, so it marked it as
unavailable.

[Anon Anon]

Thanks for the update Stuart,

Yes, SA will send TCP - SYN packets to the server port to monitor passively the availability of the server. But it is showing "unavialble"(In red) but originally the server is up and running fine and the concern application also running fine.

Is this red show only the server is not available from SA point of view..

Kindly clear me on this

[Terence Mills]

Thanks Stuart. Good explanation. Is this Muthukumar? I took your support issue. Thanks for opening. The answer is basically what Stuart said. That it is how it works.
The causes could be apparently networking, Like Stuart said, if the TCP connection test fails the server will show as unavailable. The tcp connection could of failed due to it not being
able to access this server over the network, even though it is up and running

From: CA Infrastructure Management Global User Community (eHealth/Spectrum/NetQoS) [mailto:[e-mail]]
Sent: Thursday, February 07, 2013 2:10 PM
To: [e-mail]
Subject: RE: Re: [CA Application Delivery Analysis] Server unavailability

Thanks for the update Stuart,

Yes, SA will send TCP - SYN packets to the server port to monitor passively the availability of the server. But it is showing "unavialble"(In red) but originally the server is up and running fine and the concern application also running fine.

Is this red show only the server is not available from SA point of view..

Kindly clear me on this
Posted by:mselvaraj
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[Stuart Weenig]

Terence is right, if the collector's management IP address cannot
communicate via that port to the server, then SA will show it down, even if
the server is up. However, the test will only run if the packet capture
coming into the collector shows no data for the full 5 minutes.