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Forum Discussion

Yehuda_Pinchas's avatar
Yehuda_Pinchas
Icon for Nimbostratus rankNimbostratus
Sep 30, 2015

The pool members up/down for no reason

Dear F5 guys,   We have a serious problem, where pools are fluctuating UP/Down. When all pool members are down, the pool will be down and also VS will be down. Users are complaining as they can't ...
application delivery
availability
LTM
management
monitor
IheartF5_45022's avatar
IheartF5_45022
Icon for Nacreous rankNacreous
Sep 30, 2015

Either you have a network issue which is causing your monitors to fail, OR your servers are having problems you aren't aware of OR the monitors themselves need to be tuned to be more appropriate to your specific servers.

A monitor will fail if;

  • the server does not respond
  • the server does not respond in time
  • the server does not respond with the expected response

You need to perform a tcpdump to ascertain which one (or more) of these is causing your issue. The following will display hex/ascii of healthcheck traffic on the screen;-

tcpdump -i0.0:nnn -s0 -XXX -vv host x.x.x.x and port yy

where x.x.x.x is the non-floating self-ip of your LTM, and yy is the port used by your pool.

Or if that causes too much traffic you can output to file and view in Wireshark;-

tcpdump -i0.0:nnn -s0 -w /var/tmp/health.cap host x.x.x.x and port yy

What kind of monitors are you using?