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NetworkFreelancer's avatar
Feb 12, 2025
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Want to understand BigIP F5 LB Active/Active setup

I am exploring HA setups of F5 Load Balancer. I have question on F5 Active/Active HA setup.   What will be uses cases of having both F5 LB in Active/Active mode? How traffic can be distributed bet...
  • f51's avatar
    Feb 13, 2025

    F5 can be set up in two ways: Active/Active and Active/Standby. An Active/Active setup has some cool benefits, like better high availability, improved scalability, and better resource use. In this setup, both load balancers are busy handling traffic, so if one fails, the other can keep going without much trouble. This is especially helpful for apps that get a lot of traffic, because it spreads the load out so no single device gets overwhelmed. It also helps spread traffic to the closest data center, which means users get faster response times. By using both devices, you make sure they both help out, instead of just one sitting idle.

    But there are also some things to keep in mind about an Active/Active F5 LB setup. First, it can be a bit tricky to set up and keep running. You have to make sure traffic is evenly distributed and that both devices are in sync. Troubleshooting can also be a bit harder, since problems can come from the two active devices working together. There’s also a chance that the network can get too busy, which could slow things down if you don’t manage it well. And lastly, it’ll cost more because you need two devices that can handle a lot of traffic, which means you’ll need more powerful and expensive hardware.

    For your other query to Aswin

    You’ve got the right idea about traffic-groups in an F5 Active/Active setup. Traffic-groups are like traffic managers that help you distribute traffic in this configuration. Each traffic-group can be linked to a specific set of virtual servers, and you can assign these groups to different devices in the cluster. This way, you can decide that traffic ‘A’ should go through F5-1 and traffic ‘B’ should go through F5-2, based on how these virtual servers and their traffic-groups are set up. By carefully configuring traffic-groups, you can make sure that the workloads are balanced just the way you want them. This setup is all about optimizing resource usage, making sure there’s redundancy, and keeping things super high-available.

    Now, in a general Active/Standby setup, you usually make changes on the Active device, and those changes automatically get copied to the Standby unit. But in an Active/Active setup with F5 devices, things are a bit more complicated because both devices are handling traffic at the same time. So, when you make changes in an Active/Active setup, you need to be extra careful to make sure they’re consistent on both devices. F5 has a cool feature called Device Service Clustering (DSC) that helps you do just that. When you make a change on one device, DSC makes sure that the changes are copied to the other devices in the cluster, keeping everything in sync and consistent. It’s important to plan and manage these changes carefully to avoid any problems and make sure everything runs smoothly across your Active/Active setup.