F5 Questions

 

1.Difference between least connection and fastest connection

they both look the same. the server who process request fast will also be the one with least connection, so how to differentiate between them.

Least connection doesn;t take into account the layer 7 request?

 

Ans:

Fastest is based on fewest outstanding L7 request - this is equivalent to HTTP_REQUEST (one way) only. Thats 1 count!

If the Server respond with HTTP_RESPONSE it will decrement to 0 because its not an outstanding request anymore. Its now a connection

 

Least Connection - based on few connection,  L7 - based on L7 request. Connections and request are two different things. It will only be considered a connection if Server has responded to the request.

 

For Least Connections - I used SSH application as the best example to test, because they are long lived applications. HTTP or Web based applications have connection but it tears down immediately.

 

Summary:

Least Connection is based on fewest number of CONNECTION which is a complete transaction between Cient-Server

Fastest is based on fewest OUTSTANDING L7 REQUEST which is half/one-way client-server transaction.

 

Note: No one uses Fastest because not too many people understand the concept :)

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2. Regarding Upgrade Topic

Do we any application which we can use to verify the configuration after upgrade like checksum or hash file which can tell us that older config and config after the upgrade is matching?

After the upgrade a few iRule may not work as expected, is it happen because with upgrade few syntaxes get change for iRules?

This query may sound stupid but got confused with HD concept as you said we need to upload a new image in new volume is it due to space constrain in the virtual environment or in regular envrioment also need to pick different volume for new image ?

 

Ans:- Based from experience and research there is no such tool.

Yes, iRule may not work after upgrade and I experienced this before. I opened a Case and we converted some iRule to a Local Traffic Policy and it went well.

 

The volume concept is more for segregation of software image and this is mandatory for both physical and virtual environments. Yes, you need to pick different volume per new image. You Activate software per volume. In the example below, you choose which volume to load the image upon boot up. Currently its using v13.1 but if you want to upgrade to v15.0, you would activate HD 1.3

 

HD 1.1 - v13.1 (ACTIVE)

HD 1.2 - v14.1

HD 1.3 - v15.0

 

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