Forum Discussion
GIS1STOP_182395
Nimbostratus
NimbostratusDoes LTM really support Zero downtime?
In web application system, there are two IIS web servers running the same web site. Above them, there is one LTM as load balancer. I was told, if one web server is shutdown, it will take up to 90 sec...
Hi, the monitor interval and timeout settings are user configurable. You could set the interval for one second and the timeout for 4 seconds, after which a connection load balanced to that downed pool member would be handled according to the "Action on Service Down" setting in the pool configuration.
Too aggressive interval/timeout settings will probably put too much traffic on the wire and too much load on your servers...you'll want to adjust them appropriately for your application.
If you are using the IIS iApp, the template does default to 30/91 for interval/timeout, but allows you to specify the monitor interval and adjusts the timeout to (interval x3) + 1 second. If you use a 5 second interval, the timeout will be 16 seconds.
nathe
Cirrocumulus
CirrocumulusOther ways that the LTM can improve application availability, and get somewhere to your zero downtime goal is Passive Monitoring (https://support.f5.com/kb/en-us/solutions/public/7000/400/sol7440.html) and Action On Service Down (https://support.f5.com/kb/en-us/solutions/public/15000/000/sol15095.html).
I know your looking at the bigger picture but i hope this is useful anyway.
N