Help debugging cacheability / ttl information?

Denis Brækhus denisb at
Mon Feb 18 09:26:28 CET 2008

----- "Dag-Erling Smørgrav" <des at> wrote:
> > setup with regards to TTLs and cacheability. I'd like to be able to
> > inspect a specific cached objects TTL to see if my "set obj.ttl"
> > overrides actually work or not. What is the best way to do that?
> You should get a varnishlog entry for the TTL computation when an
> object is retrieved from the backend, but there won't be a log entry
> for VCL changing the TTL...

Ok, thanks. I guess what I am missing is a VCL debugger of some sort
;) But joke aside, the logentries are definitely helpful, there are
only so many of them it is sometimes a bit overwhelming when you do
not know exactly what you are looking for.

> > On the client I use firebug, so all headers and responess are
> > readily available on that end. The reason I don't think everything
> > is as it should is that the Age header is very low most of the
> time.
> Instead of Firebug, have you considered using the following:
> while :; do
>     wget -O/dev/null -S 2>&1 | \
>         grep -i '^age:' ;
>     sleep 5 ;
> done

Yes, I used curl in a similar fashion, and again the age header seemed
to be a bit low. But it seems the minimum TTL parameter for varnishd
"fixed" this situation for us.

> > For the record we are still at varnish 1.0.4 [...]
> 1.0.4 is almost a year old...  why not 1.1.2?  It has *much* better
> support for examining and modifying HTTP headers.

Well, 1.1.2 is being considered now, but up until 1.1.2 my impression
has been 1.0.4 was the best build with regards to stability. We have
had varnish nodes running for 6-8 months now without interruption or
any problems whatsoever.

List traffic sort of indicated there were always some snags with the
1.1.x builds, but 1.1.2 seems to be working fine for people I gather?!


More information about the varnish-misc mailing list