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RandyMoran_1359's avatar
RandyMoran_1359
Historic F5 Account
May 01, 2017

Exchange 2013 - Need a way to down the combined virtual server in the the event any one pool is down

I have an Exchange 2013 setup deployed via iApp on TMOS 11.6.0, using the combined virtual server method (one IP address, multiple pools load balanced via iRule). There are multiple data centers involved, all also part of a GTM config.

 

We had a recent situation wherein only one of the pools at one of the datacenters went down (it was the mapi-to-http pool, which rendered the Exchange virtual server useless) but, because the virtual server remained up, the GTM was still resolving users to that datacenter whereupon the users where experiencing connection failures. If the pool failure would've marked the virtual server down, the GTM would've marked that Exchange vs unavailable and the users would've been sent elsewhere. As it was, I had to make this work manually by administratively disabling the pool in the GTM.

 

Here are my questions:

 

  1. Is there a way to set the virtual to become disabled upon the failure on ANY ONE of the pools in the single virtual server/multiple pool configuration?

     

  2. By what method is the virtual server status in this configuration currently determined? All of the pools have monitors set, of course, but there is NO default pool associated with the virtual server. There doesn't appear to be any monitor logic in the iRule, so is it merely the presence of the valid, named pool reference in the iRule that sets the virtual server to green?

     

Thanks, Randy

 

application delivery
iRules
LTM

1 Reply

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  • nathe's avatar
    nathe
    Icon for Cirrocumulus rankCirrocumulus
    May 01, 2017

    RandyMoran, see this solution to explain VS status with pools assigned by an irule k6514

     

    So from this solution you'd need to down all pools for a VS to go down. The way to possibly do this is for each and every pool referenced in the irule, add another monitor (or monitors) with alias address and ports of pool members in all other pools and set set Availability to All. You only need to do this for one pool member from another pool but this will down the VS if ONLY that pool member goes down in the other pool. You'd need to turn off Strict Update to. Granted this is probably complex and will need a lab.

     

    Hopefully other DCers may have a better solution.

     

    N