Le 16/09/2011 08:55, Jorge Nerín a écrit :
On Thu, Sep 15, 2011 at 11:29, Aurélien Lemaire <[email protected]
<mailto:[email protected]>> wrote:
Good day folks,
First of all, varnish is an outstanding piece of software that my company
and i are addicted to. So thanks to all the coders.
Here is my problem :
I allocated varnish 1G of RAM on a website that can have more than 2 Go of
possible cacheable objects . Not to worry though as any proxy-cache system
should smartly nuke old objects to make place to new one to live
peacefully within its allocated RAM. And that's where Varnish behave
unexpectedly : each time it need to nuke SOME objects : it nukes ALMOST
ALL of them (often ~80% of my 35k objects) which is quite aggressive ;
thus i lost almost all my cache....IRK !
3 Munin graphs attached to see the problem clearly : big drop each time a
nuking happens.
To make sure my pbr is about varnish nuking system : i increased from 1G
to 3G(more than the max possible 2G cacheable objects) on another varnish
of this platefom (this website is delivered by multiple front/varnish
server all stricly similar and independant) and this issue disappeared (no
more nuking : no lost of ~80%of my objects)
Here is my env :
Debian 5.0.8 64 bits on 2.6.32-5-openvz-amd64 kernel
Varnish 2.1.3 SVN 5049:5055(debian package 2.1.3-8)
200 varnish 's worker threads running constantly (no issue on workers)
30req/s average with 60/s in peak
Daemon run as such :
/usr/sbin/varnishd -P /var/run/varnishd.pid -a :80 -T localhost:6082 -S
/etc/varnish/secret -f /etc/varnish/serverx.vcl -w 100,1024 -s
file,/var/lib/varnish/serverx/varnish_storage.bin,3G
Here a quick varnishstat -1 :
Is it normal varnish behaviour ? sounds like a bug to me.
Am i missing some tuning (lru_interval) to soften the nuking algo ?
Do you need more info ?
helps appreciated here ;-)
Regards, Aurelien Lemaire
It could be someone downloading a large file (like a ~700Mb iso file) and
varnish nuking objects to make room for this file (even if its configured to
not cache it).
Try to get a varnishlog trace of the moment the nuking begins.
--
Jorge Nerín
<[email protected] <mailto:[email protected]>>
This website does not content any files bigger than a couple of Mb.
Will see what i can do to get the varnishlog during the nuking.
--
aurelien lemaire
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