Varnish may be marking your backend as "unhealthy" because you're failing too many health probes during this phase. When Varnish does backend health polling, it opens a *new* tcp connection to the backend with a preconfigured request.
I would increase the timeout, window, and/or threshold to see if you can rule this out. You can read more about backend polling here<https://www.varnish-cache.org/trac/wiki/BackendPolling> . On Sun, Feb 10, 2013 at 6:35 AM, Tristan CHARBONNIER @ Crealya < [email protected]> wrote: > Hello,**** > > ** ** > > First, I want to thanks everyone who is contributing to this great piece > of software! Indeed, it’s working very well and it’s very efficient.**** > > ** ** > > I just encounter a small problem : I use varnish/squeeze v2.1.3-8 on a > Debian Linux 6.0 web server with the kernel v2.6.32-5-amd64.**** > > I use Virtualmin to manage this webserver and I set up Varnish on top of > apache2/squeeze v2.2.16-6+squeeze10.**** > > ** ** > > During the logrotate process, Varnish gives 503 errors. I traced the > problem to the multiple apache2 graceful restart that are done during this > process.**** > > Indeed, I host plenty of websites (more than 100) on my web server and, > for each one, I have a block like this in my ‘/etc/logrotate.conf’ file:** > ** > > ** ** > > /var/log/virtualmin/mywebsite.fr_access_log > /var/log/virtualmin/mywebsite.fr_error_log {**** > > rotate 5**** > > weekly**** > > compress**** > > postrotate**** > > /usr/sbin/apache2ctl graceful ; sleep 5**** > > endscript**** > > }**** > > ** ** > > So, during the logrotate process (which lasts for 20 minutes), there is > 100+ graceful restart of apache. ‘graceful restart’ are not supposed to > terminate existing connections so I don’t understand why Varnish fails to > work: probably a mistake on my side!**** > > ** ** > > In my VCL file, I just have “backend apache { .host = "88.190.19.00"; > .port = "8080"; }” block along with the usual ones (acl purge, vcl_fetch, > …). I use the default Varnish configuration file, except that I raised the > memory to 4G and use ram to store the cache.**** > > ** ** > > Any clue on how I can solve this small problem?**** > > ** ** > > Thanks in advance,**** > > ** ** > > Tristan CHARBONNIER**** > > ** ** > > ** ** > > _______________________________________________ > varnish-misc mailing list > [email protected] > https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc >
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