Forum Discussion
tarsier_90410
Nimbostratus
NimbostratusIs global memory shared across HA LTM's?
We are getting ready to buy a new pair of LTM's to replace our stand alone LTM, and I am trying to get ready to update our iRules before they arrive. Do global variable values fail over, or would they need to be handled a special way?
- The_BhattmanHi Tarsier,
As far as I can tell Global variables aren't transfered over during failover. However, existing connections (if mirroring is turned on) will failover. I do believe that the irules would re-process the irules on the next connection. Of course this is all based on my observation
Bhattman 
hoolioCirrostratus
As Bhattman suggests, global memory isn't synched to the peer. I guess the benefit versus overhead doesn't justify it.
You can use 'info exists ::my_global_var' (Click here) to check if a variable exists before trying to use it. But it would probably make sense to just reset the connection if a required global variable doesn't exist (which is what should happen when you get a runtime TCL error trying to access a variable that isn't set).
Aaron
tarsier_90410Thank you for the feedback. Unfortunately, that is the answer I expected.- The_BhattmanSorry to disappoint ;-)
