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Thong_196816's avatar
Thong_196816
Icon for Nimbostratus rankNimbostratus
May 25, 2015

network failover/serial cable for HA

for HA configurations, there are 3 options

 

  • network failover

in network failover the heartbeat is the network packet

 

  • serial failover

serial cable failover is just checking a voltage heartbeat between the two systems.

 

  • network and Serial failover

I not sure does it mean failover only take place when network and serial both are failed or ? if use both, how to test if it is working?

 

  • network and Serial failover

     

    If you configure a BIG-IP high-availability pair to use network failover, and the hardwired failover cable also connects the two units, hardwired failover always has precedence; if network failover traffic is compromised, the two units do not fail over because the hardwired failover cable still connects them.

     

    sol2397: Comparison of hardwired failover and network failover features

     

    https://support.f5.com/kb/en-us/solutions/public/2000/300/sol2397.html

     

14 Replies

  • svs's avatar
    svs
    Icon for Cirrostratus rankCirrostratus

    Hi Thong,

     

    do not use the hardwired failover except you need failover times under 1 second. There is so much to keep in mind when the hardwired failover is used. For example, that in most cases there will be no failover during a reboot of a node. Also, as nitass already stated, there will be no software failover as long as the secondary node is still physically available through the serial cable.

     

    In my mind the hardwired failover doesn't make sense at all. There may be cases, where it makes perfect sense, but I'm pretty sure those cases are rare. I removed the hardwired failover on every single customer installation. Since there is no hardwired failover software updates are working as expected.

     

    Greets, svs

     

  • network and Serial failover

     

    If you configure a BIG-IP high-availability pair to use network failover, and the hardwired failover cable also connects the two units, hardwired failover always has precedence; if network failover traffic is compromised, the two units do not fail over because the hardwired failover cable still connects them.

     

    sol2397: Comparison of hardwired failover and network failover features

     

    https://support.f5.com/kb/en-us/solutions/public/2000/300/sol2397.html

     

    • InquisitiveMai's avatar
      InquisitiveMai
      Icon for Cirrostratus rankCirrostratus

      Has anybody disconnected the Serial/Hardware cable when Network failover shows OK for atleast 1 network? Has it caused any failover event, even when network failover was looking good? 

    • Thong_196816's avatar
      Thong_196816
      Icon for Nimbostratus rankNimbostratus
      finally.. will use LAN cables to connect between active-standby devices (not more using network failover - connect to switch). I will assign IP for interface 1.7 on both units , hope this works.
  • network and Serial failover

     

    If you configure a BIG-IP high-availability pair to use network failover, and the hardwired failover cable also connects the two units, hardwired failover always has precedence; if network failover traffic is compromised, the two units do not fail over because the hardwired failover cable still connects them.

     

    sol2397: Comparison of hardwired failover and network failover features

     

    https://support.f5.com/kb/en-us/solutions/public/2000/300/sol2397.html

     

    • Thong_196816's avatar
      Thong_196816
      Icon for Nimbostratus rankNimbostratus
      finally.. will use LAN cables to connect between active-standby devices (not more using network failover - connect to switch). I will assign IP for interface 1.7 on both units , hope this works.
    • nitass's avatar
      nitass
      Icon for Employee rankEmployee
      both units will go active (i.e. active-active).
    • Thong_196816's avatar
      Thong_196816
      Icon for Nimbostratus rankNimbostratus
      Hi Nitass, what is the outcome if both network and serial cable failed in this case?