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smurteira_23292's avatar
smurteira_23292
Icon for Cirrus rankCirrus
Apr 08, 2016

About F5 Cluster Config Sync and save changes

I just setup an F5 Cluster with 2 BigIP 2000 units. Currently I have automatic config sync configured. My understanding with automatic sync is that it will automatically sync but not save the changes. I also understand that if the config is not saved, the changes are lost after a reboot. So let's say we have the following scenario. I usually go into my units and make changes and allow automatic sync but usually forget to go into the console to save the changes to Unit2. Unit1 goes down and I have a failover to Unit2, soon after, for whatever reason, Unit2 also goes down. Upon investigating I'm only able to bring up Unit2. Are all my changes lost? Have I reverted back to the latest time I saved the config on Unit2?

 

application delivery
BIG-IP
cluster
config sync
f5
LTM
save

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  • Daniel_Varela's avatar
    Daniel_Varela
    Icon for Employee rankEmployee
    Apr 08, 2016

    Hi according to the documentation you can change default behavior (https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/bigip-device-service-clustering-admin-11-5-0/7.htmlunique_589421575) :

     

    Alternatively, you can change the default behavior so that the system automatically saves configuration changes on >target devices after an automatic config sync. You make this change by logging into one of the devices in the device >group and, at the tmsh prompt, typing modify cm device-group name save-on-auto-sync true.

     

    Warning: Enabling the save-on-auto-sync option can unexpectedly impact system performance when the BIG-IP system >automatically saves a large configuration change to each device.

     

    Anyway if one device goes off, if you log into the other and you makes a change on it this will will save the config in that device again. Think about the situation where you have both devices off is really really small, that never happened to me.