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Forum Discussion

wtwagon_99154's avatar
wtwagon_99154
Icon for Nimbostratus rankNimbostratus
Feb 10, 2010

Health Check Issues

The Scenario:     We are performing some load testing of an application and are using a health check as follows:     GET /blah/blah.asmx HTTP/1.1\r\nUser-Agent:Mozilla\r\nhost:bl...
management
monitoring
hoolio's avatar
hoolio
Icon for Cirrostratus rankCirrostratus
Feb 10, 2010
The timeout = 3 x interval + 1 is a best practice as it allows the server three chances to respond successfully before being marked down. A 5 second interval has been a good place to start as a test request this often shouldn't overload the servers. And 16 seconds is not a horribly long time to wait to mark a failed server down.

 

 

If 16 seconds is too long for you to wait to mark a dead member down, you could reduce the timeout or use an iRule to mark the pool member down (LB::down in the LB_FAILED event). If your servers are being overwhelmed with too many requests, you could extend the interval and timeout longer than 5 / 16.

 

 

I'd still try troubleshooting why it's failing with the default of 5/16 during a light load test before tinkering too much with the monitor timings.

 

 

Aaron