Forum Discussion

daboochmeister's avatar
May 11, 2015

Why default pool "Reselect Tries" to 0? Any downside to higher values? Wouldn't that prevent client failures?

I'm trying to digest Sol10640 (https://support.f5.com/kb/en-us/solutions/public/10000/600/sol10640.html) and all its implications.

 

The "Reselect Tries" seems to address a frequent customer complaint - that when a server goes down (but before a health monitor has marked it as down), the F5 will still send client connection attempts to it, and fail the client's connection if the attempt to connect to the real server fails.

 

Yet the default for "Reselect Tries" is 0. Why is this? Does that imply that there's some significant downside to consider in setting it above 0?

 

I've never seen general guidance, but I would think for e.g. HTTP proxies, setting it to " of pool members - 1" might be the best approach. No?

 

thx!

 

  • My main concern would be for persistence, since re-selecting another pool member before the F5 has marked the original selected pool member down may cause more problems than it solves as re-selecting may break the persistence paradigm. There are many reasons to have a failed TCP connection that might not be indicative of a node truely being down.