[+] Re: Breaking Varnish

Poul-Henning Kamp phk at phk.freebsd.dk
Wed Jan 28 19:09:37 CET 2009

In message <20090128180448.GD28138 at digdug.corp.631h.metaweb.com>, Niall O'Higgi
ns writes:

>Transaction rate:            3776.65 trans/sec
>Throughput:                     1.68 MB/sec
>Concurrency:                   28.28
>Does the parent process give up on restarting the child after a
>certain number of failures?  I was surprised by the eventual complete
>exit of varnishd with the message:
>Pushing vcls failed: CLI communication error

It shouldn't do that, it should be able to restart it forever.

>Also, Varnish seems to be able to handle up to about double that load
>for a while (we got up to 6701 t/sec), then it dies as above.  Seems
>like it takes around 2-3 hours for the varnishd parent process
>to die.

Once you get to that level of load, the ability of the scheduler
to not do something stupid is paramount for survival.

Try to increase the "cli_timeout" parameter, it is probably set a
bit on the aggresive side by default.

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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