[Varnish] #85: High number of "worker threads not created" and "overflowed work requests"

Varnish varnish-bugs at projects.linpro.no
Fri Feb 16 14:08:01 CET 2007

#85: High number of "worker threads not created" and "overflowed work requests"
 Reporter:  Thias     |        Owner:  phk
     Type:  defect    |       Status:  new
 Priority:  normal    |    Milestone:     
Component:  varnishd  |      Version:  1.0
 Severity:  normal    |   Resolution:     
 Keywords:            |  
Comment (by Thias):

 After "stabilizing" some real production traffic to the varnish server,
 it's pushing between 100 and 160Mbps on it's public interface, and getting
 between 10 and 30Mbps from the backend on its private interface. Not
 bad... but : When I see the "Create worker thread failed 12 Cannot
 allocate memory" appear (I'm running "varnishlog -i Debug" to catch
 those), the outbound traffic drops to 30-60Mbps, and a test to a web page
 shows that all images are loading very slow. Those requests are
 unfortunately not just "a bit slow" *sigh*

 I've now tried passing -w1,230,120 but although I now don't get to see the
 errors, things stop working properly after a while in a similar way, and
 "worker threads limited" and "overflowed work requests" start to increase
 a lot :
          230         0.00         1.54 N worker threads
          230         0.00         1.54 N worker threads created
            0         0.00         0.00 N worker threads not created
        16672       534.92       111.89 N worker threads limited
           93       -29.88         0.62 N queued work requests
        16902       534.92       113.44 N overflowed work requests
         9044         0.00        60.70 N dropped work requests

 If the 32bit limitations aren't going to get worked around anytime soon,
 I'll definitely try to get my hands on a 64bit machine to do some more
 testing, although that won't be so easy...

Ticket URL: <http://varnish.projects.linpro.no/ticket/85>
Varnish <http://varnish.projects.linpro.no/>
The Varnish HTTP Accelerator

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