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FZ_101142's avatar
FZ_101142
Icon for Nimbostratus rankNimbostratus
Aug 29, 2012

Load Balancing Application & Database Servers

Hi All,

 

I am new to F5 and need some recommendation, may be someone can help.

 

 

Q1. I have 4 web servers load balancing with source IP persistance and round robin load balancing. These web servers talk to 4 application servers. I want one to one mapping among each web and application server and in case of a failure, I want the web server to be able to communicate to next available application server. What is the best way to achieve this and what load balancing method should I use.

 

 

Q2. The second tier is the 4 application servers communicate with two database servers with Priority group values of 100 and 50. I want application servers to communicate with DB1 databse servers with higher group priority and in case of a failure of db1 i want the apps server to go to the db2 databse server. In case the db1 comes up, I want all connections kept to db2 and not back to db1 and go to db2 only in case of failure of db2

 

 

I hope someone can help and there is a solution. I would not mind looking at any best industry practices available.
config
design

1 Reply

  • Ferg_104721's avatar
    Ferg_104721
    Icon for Nimbostratus rankNimbostratus
    Sep 07, 2012
    Q1 I am not sure you can do what you are asking but i may be interpreting the question incorrectly, have a read of "Specifying the load balancing method" Unless you write is in an iRule

     

    http://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/ltm_configuration_guide_10_0_0/ltm_pools.html1215305

     

     

    If they where 4 separate webserver as VIPS and you had a GTM then you would set the last resort pool and if the true pool (server) is down then it would use servers listed. IF you GTM you may be able to do the same with an irule, have your normal VIP setup but also have an irule so that if the pool goes down it select another pool.

     

     

    Q2 I think you will fall into the scenario again where you will ned to use an iRule. By nature prioirty group will pick the higher prioty. You could write an irule to LB based and set priority but if the pool goes down change the priority and that way the the active will always stay highest.