limit # of pool members that will be taken out of service

Hi Ken,

 

 

There isn't any logic in default LTM config to stop marking pool members down if they fail the monitor checks. You could potentially build this into an external monitor script using a template:

 

 

http://devcentral.f5.com/wiki/default.aspx/AdvDesignConfig/TemplateForExternalLtmMonitors.html

 

 

If you want to get a count of the total members of a pool you can use the members command. To get a count of the active members you can use active_members:

 

 

http://devcentral.f5.com/wiki/iRules.members.ashx

 

http://devcentral.f5.com/wiki/iRules.active_members.ashx

 

 

You could check the ratio of active members / total members to determine if you want to use a second pool.

 

 

Aaron

Here's an untested example of the members ratio logic I was thinking of:

when CLIENT_ACCEPTED {

 Check if there are less than half of the default pool members up
if {[expr {double ([active_members [LB::server pool]]) / [members [LB::server pool]] < .50}]}{
pool second_pool
}
}

Aaron

Thank you hoolio. That is very helpful!