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sansar_146851's avatar
sansar_146851
Icon for Nimbostratus rankNimbostratus
Feb 08, 2016

Mirroring

We want to try enable connection and persistence mirroring but also want to be sure effect of mirroring on device performance. We have appr. 2 gigs of traffic on 8900s. We know it depends of our tps, kind of traffic, timeouts etc. but can you help me about which resources will be more utilized when we use persistence and is there a calculation method of that?

 

3 Replies

  • Mirroring connection information involves sending a copy of the mirrored flows to the other BigIP for processing - it doesn't just send summary or state information, so this means that the network path your mirror traffic flows over needs to be able to handle the total bandwidth of all data being mirrored. If you're mirroring a single virtual server, for example, then the total traffic to and from that server will be mirrored, in order for both boxes to maintain the same connection table and thus ensure a seamless failover. This is only really necessary when your applications can't tolerate a transport layer failure on a long lived connection. For short lived connections such as HTTP requests, there's little value in mirroring the flows.

     

    But if you're only mirroring persistence data, then this reduces your bandwidth requirements significantly, as only the persistence records are mirrored

     

  • Thank you, what about the effect of mirroring on resources like cpu and memory, can it really cause resources issue on active machine and can we calculate or predict it?

     

    • IanB's avatar
      IanB
      Icon for Employee rankEmployee
      It's difficult to predict, as it depends on the nature of your traffic, the type of mirroring you're performing, the concurrency of your connections, and so forth, and of course, whatever else the BigIP is doing at the same time. The best thing to do is to keep an eye on the CPU usage shown in the dashboard as you increase your load.