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Forum Discussion

Florin_Andrei_1's avatar
Florin_Andrei_1
Icon for Nimbostratus rankNimbostratus
Jan 21, 2010

GTM, active/passive and split-brain

The situation:   A pair of redundant sites, functionally equivalent (hardware-wise too, almost identical), geographically separated.   A private DS3 line in between, used to synchronize data...
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Max_Q_factor's avatar
Max_Q_factor
Icon for Cirrocumulus rankCirrocumulus
May 19, 2015

I will give you my thoughts on this for each behavior you are asking about:

 

1. Split brain is a bit difficult to enforce and you have to be willing to get creative, but ultimately you could do things like add an additional TCP monitor to the pools (either GTM or LTM) that reference the IP and 443 management port of the GTMs directly (Alias Address and Alias Service Port respectively), also look at the minimum monitors up, as well as reversing.

 

2. Preserving the current state is pretty easy when using the "manual resume" option in the monitor. Once the monitor is tripped the pool member will stay down until you manually re-enable the pool member. I see manual resume used quite a bit on database virtual servers.

 

As a bonus! If you have some sort of witness server, you might want to look at creating a monitor that queries the witness server for service availability, and/or using the appropriate database monitor to query a value in a table that reflects the operational state of the database.