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Thiyagu_343098's avatar
Thiyagu_343098
Icon for Nimbostratus rankNimbostratus
May 02, 2018

VLAN failsafe

Hello All, I want to know more about the VLAN failsafe option. Could you please help me to know

 

1- in which scenario we have to use the option? 2- What are the drawback of this option? 3- what are the best practices of configuring failsafe VLAN

 

I have encountered an issue where because of failsafe VLAN configuration that has cuased an outage due to both the primary and seconday went to an standby/standby state?

 

Is there any way we can avoid this issue?

 

Regards, Thiyagu

 

Is

 

application delivery
BIG-IP
LTM

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  • Lee_Sutcliffe's avatar
    Lee_Sutcliffe
    Icon for Nacreous rankNacreous
    May 02, 2018

    There is no requirement to use VLAN failsafe, it is used to trigger a failure condition in the event that F5 detects a loss in network activity on a given VLAN. It is not the most graceful of HA detection methods but can be useful in some environments. Vlan failsafe is slow, the minimum timeout is 10 seconds which is unacceptable in many environments.

     

    I would recommend looking at HA Groups/Fast Failover as you can have a more granular failure scenario, such as pools going down or the loss of a default gateway. It uses a scoring mechanism and will failover more quickly than traditional methods such as VLAN failsafe.

     

    Manual Chapter: Understanding Fast Failover

     

    K16947: Best practices for the HA group feature

     

  • youssef1's avatar
    youssef1
    Icon for Cumulonimbus rankCumulonimbus
    May 02, 2018

    Hello,

     

    VLAN failsafe allow to monitor certain aspects of the system or network. This functionnality can detect a problem with a VLAN (Monitors traffic on a VLAN), and take some action, such as restarting the service or failover. The default action is Reboot.

     

    What I now, when a device encounter a Networ problem (On a monitoring VLAN), the system initiate failover and switch control to the standby device regardless of the other equipment.

     

    that means that we can potially have the 2 standby equipment (I already had this problem).

     

    To solve this problem, I gave up vlan failsafe an I used HA group (that are more flexible and smart). You can create a pool with your GW and create a transparent monitor. then Put a different Weight on both device... That allow you to failover when a vlan fail but always have an active memenber.

     

    Hope that it's clear for your.

     

    Regards,