Upstream least_conn behavior irregularity

John Watson john at
Thu Mar 21 08:45:14 UTC 2013

Was investigating some issues today when we noticed that least_conn wasn't
behaving as expected.

upstream backend {
  server unix:/tmp/sock-1.sock;
  server unix:/tmp/sock-2.sock;
  server unix:/tmp/sock-3.sock;

The expected behavior for 4 simultaneous requests it should distribute them:
sock-1: 2
sock-2: 1
sock-3: 1

However, what we're seeing is:
sock-1: 3
sock-2: 1
sock-3: 0

Which coincidentally lines up with the number of requests a socket can
service simultaneously.

This is using 1.2.7
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