Keepalive checks skew hit ratio, need ideas on how to fix

[Allard Hoeve]

Hello all,


I run Varnish on a number of servers now, but one thing that is regularly
bothering me is how keepalive checks by ip_vs skew the hit ratio on slow
servers (e.g. at night). Is this something that has come up but that I've
missed? I'd like to find a solution to this problem, but the source code is
daunting :) I'd like to probe you guys on ideas on how to get better stats
in my (not very uncommon) scenario.


An idea that I've had is to provide a way to mark certain hits as
*req.do_not_log
(*in vcl_recv?) or *req.no_statistics*. This would prevent that connection
from getting used in statistics. Places where client_req is incremented
would have to skip that increment. Other places would not increment
cache_hit, cache_hitpass or cache_miss. It would touch a lot of code, but
when done is backwards compatible, because those who don't set the counter
are fine.


Another way is to count twice, one *client_req* and one *
client_selective_req* or so.


Any thoughts?


Best,

Allard Hoeve
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