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Kundan_Kumar_21's avatar
Kundan_Kumar_21
Icon for Nimbostratus rankNimbostratus
Aug 20, 2015

100% Server Availability

We are having 2 servers which is serving the client request through BIG-IP. We want to upgrade both servers and it requires reboot. How can acheive 100% availability of the server by configuring the ...
application delivery
LTM
management
Kevin_Stewart's avatar
Kevin_Stewart
Icon for Employee rankEmployee
Aug 21, 2015

Generally speaking, you'd have 2 members in a pool, and that pool would have a monitor applied to it. That pool would be attached to a virtual server and clients would access the application through the virtual server. The monitor attached to the pool would guarantee that new requests would not be sent to an offline server (during reboot). In the pool's properties, you'd also want to select 'Reselect" under the Action on Service Down option.

 

Providing "100% availability" though isn't always that simple. There are other factors to consider:

 

  1. Are there active "sessions" on a server when you reboot and will sending existing users to a new server break the user experience? This is usually beyond the scope of load balancing and may require "shared" session table access between the applications.

     

  2. What qualifies a failure event? A good monitor should be actively looking for whatever that is (not just a ping).