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Shahrzad_84598's avatar
Shahrzad_84598
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Feb 22, 2015

GTM with or without LTM?

Hi there, I need to know, if we have web servers to publish on web in backup and main data centers, is it a must to have GTM and LTM toghether in every DC, or for example in backup site(which has the same web services published)is it possible to have just the GTM without LTM and the GTM directly doing the health monitor of these services? thanks Shahrzad

 

10 Replies

  • you can think gtm is dns server (but intelligence). one gtm is fine but multiple provide load sharing and redundancy.

     

    ltm is server load balancer. user traffic does not go through gtm.

     

    hope this helps.

     

    • Shahrzad_84598's avatar
      Shahrzad_84598
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      Dear nitass, thanks for your reply.It helped a lot. You wrote "one gtm is fine but multiple provide load sharing and redundancy", by "one gtm" do you mean in one DC one GTM is enough, or for the whole scenario, I mean is it possible to have just one gtm for two or more DCs?Or it is a must to have one GTM and one LTM for each Data Center?
  • you can think gtm is dns server (but intelligence). one gtm is fine but multiple provide load sharing and redundancy.

     

    ltm is server load balancer. user traffic does not go through gtm.

     

    hope this helps.

     

    • Shahrzad_84598's avatar
      Shahrzad_84598
      Icon for Nimbostratus rankNimbostratus
      Dear nitass, thanks for your reply.It helped a lot. You wrote "one gtm is fine but multiple provide load sharing and redundancy", by "one gtm" do you mean in one DC one GTM is enough, or for the whole scenario, I mean is it possible to have just one gtm for two or more DCs?Or it is a must to have one GTM and one LTM for each Data Center?
  • I mean is it possible to have just one gtm for two or more DCs?

     

    yes but if that dc is down, your domain will be gone.

     

    • Shahrzad_84598's avatar
      Shahrzad_84598
      Icon for Nimbostratus rankNimbostratus
      we don`t have the GTM yet, but I read in some other questions on DEV that we need to add for example LTM virtual server objects to GTM so it can iquery about the health of those services from LTM, if it is true then without LTM how can we setup the GTM? Also does GTM integrates with other brands, like cisco ACE?
  • I mean is it possible to have just one gtm for two or more DCs?

     

    yes but if that dc is down, your domain will be gone.

     

    • Shahrzad_84598's avatar
      Shahrzad_84598
      Icon for Nimbostratus rankNimbostratus
      we don`t have the GTM yet, but I read in some other questions on DEV that we need to add for example LTM virtual server objects to GTM so it can iquery about the health of those services from LTM, if it is true then without LTM how can we setup the GTM? Also does GTM integrates with other brands, like cisco ACE?
  • if it is true then without LTM how can we setup the GTM? Also does GTM integrates with other brands, like cisco ACE?

     

    yes, gtm can monitor service on server or on other server load balancer vendor too. if there is ltm in dc, it is preferred to let gtm talk to ltm rather than talking to server directly.

     

  • If you plan to integrate GTM, I recommend not to use it on the same device combined with your LTMs.

     

    From the implementation / operation perspective a dedicated GTM appliance is much easier to handle.

     

    As DNS has it´s build-in redundancy (multiple NS records) it´s not necessary to implement GTMs as redundant pairs (device-groups) per site.