Nimbostratus
Cirrostratus
When the pool member goes down, does it continue to accept TCP connections? Does it send back HTTP 500's? Or does it stop answering TCP connection requests altogether?
What do you have the monitor interval and timeout set to? How long is it taking to mark a failing pool member down? How long do you want to have it take? You might be able to adjust the timeout to get better results.
Another option might be to detect a failure on a single connection in the LB_FAILED event (Click here). In theory, you should be able to select a new pool member and resubmit the request, but I haven't tested this myself and I've seen a few posts which indicate there are issues with this approach.
LB_FAILED event
http://devcentral.f5.com/Default.aspx?tabid=53&view=topic&postid=15238
LB_FAILED behavior, expected or not?
http://devcentral.f5.com/Default.aspx?tabid=53&forumid=5&tpage=1&view=topic&postid=15999
lb::reselect fails to select another node
http://devcentral.f5.com/Default.aspx?tabid=53&forumid=5&tpage=1&view=topic&postid=15864
How do I create a passive health monitor?
http://devcentral.f5.com/Default.aspx?tabid=53&forumid=5&tpage=1&view=topic&postid=1343313621
There is also a solution on AskF5 which describes an issue with LB::reselect. I haven't seen any additional info on the issue though.
The iRule LB::reselect command does not select the next pool member
https://support.f5.com/kb/en-us/solutions/public/8000/000/sol8033.html
Does anyone else have practical experience reselecting a pool member when one fails to respond? If so, did you use LB::reselect?
Aaron