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Does LB_Failed have the same criteria as using an HTTP Fallback Host?
Is there any difference at all between when the LB_FAILED event fires and an HTTP Fallback Host configured on an HTTP profile would fire?
We occasionally have about 0.1% of connections over a narrow 10 second period receiving a fallback host from a number of very busy virtual services. Something like 200 failed connections out of 50,000,000 per day!
Trying to track down this needle in a haystack we're trying to completely understand when the fallback 302 would be sent, and it appears that it's exactly 100% of the same reasons the LB_FAILED event would fail, which would mean that a scenario where, say, an HTTP request IS made to a pool member and then has it's connection reset etc, would NOT cause the fallback host to kick in? Once a TCP connection is established to the member, both the even and the fallback redirect can never occur?
In terms of once we're out on the wire, we're looking at only unreplied to SYN's or instantly RST requests before a 3 way handshake occurs. yup?
- hooleylistCirrostratusHi Chris,
- Chris_PhillipsNimbostratusHmmmmmmmm, so why, with a default tcp-lan-optimized profile on an HTTP vs are we getting LB_FAILED after as long as 72 seconds?? This suggests, to me at least, than the connection is (half?)opened, but maybe no data ever gets acked back from it? I'm sensing more of a subtlety about when a connection is officially deemed to have been balanced. Being 72 seconds, that naturally feels like some sort of time out period expiring...
- hooleylistCirrostratusHi Chris,
- Chris_PhillipsNimbostratusI have retransmits set to 3, But I think that that table is not at all correct. I did a test on a dev system on 10.2.0 and just saw retries (tcpdump) every 3 seconds until it hit the max, so with a fake pool member which would never connect, LB_FAILED always fired on 12001ms (well... ish). No sign of an incremental back off whatsoever.
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