Hello! Yes, it is Varnish 4.1.1-1 from the Ubuntu 16.04 repo. I'll look at the issue you've linked and see if I can match it to our situation. Thanks!
Justin -----Original Message----- From: Dag Haavi Finstad [mailto:[email protected]] Sent: Friday, December 9, 2016 4:47 AM To: Justin Lloyd <[email protected]> Cc: Dridi Boukelmoune <[email protected]>; Jason Price <[email protected]>; [email protected] Subject: Re: Hit ratio dropped significantly after recent upgrades Hi Is this Varnish 4.1 ? We have an unsolved bug open describing something very similar, https://github.com/varnishcache/varnish-cache/issues/1859 On Thu, Dec 8, 2016 at 9:26 PM, Justin Lloyd <[email protected]> wrote: > I have been doing a lot of digging with varnishtop and varnishlog, and our > VCL really didn’t change from this upgrade except as needed to migrate from > Varnish 3 to 4. As I mentioned, our web app is MediaWiki so we don't control > its caching requirements and recommendations, so what I'm trying to > understand is whether the drop in the hit rate is due to some change(s) in > MediaWiki's cookie and/or cache handling (e.g. via Cache-Control and > Set-Cookie headers) or if something in Varnish changed that affects how it > determines things. For example, a while back I had been using the Varnish > hit and miss metrics in Collectd to calculate the ratio but apparently how > those values are calculated with respect to purges changed so the hit ratio > dropped, causing me to change the ratio calculation to use incoming > connections and backend requests instead. > > That said, based on my varnishlog and varnishtop testing, I have a strong > feeling that the biggest part of the problem is thumbnail images. If you look > again at my VCL code > (https://gist.github.com/Calygos/105957a997ea3bde6b8257a1f34bbd20), you can > see I strip cookies from thumbnails so they should get cached, but I seem to > get a lot more misses than hits when watching for thumbnail URL requests > through varnishtop. I give 8 GB to Varnish and its process is typically only > around 1 to 2 GB when previous it would be at 8 GB with frequent nukes and > the occasional spike of expires that would temporarily eliminate nukes while > memory filled up again. For what it's worth, I added the thumbnail stripping > a couple of years ago due to a performance issue and it helped tremendously, > so I don't know why it would become problematic with these latest upgrades. > > Justin > > -----Original Message----- > From: Dridi Boukelmoune [mailto:[email protected]] > Sent: Thursday, December 8, 2016 6:49 AM > To: Jason Price <[email protected]> > Cc: Justin Lloyd <[email protected]>; [email protected] > Subject: Re: Hit ratio dropped significantly after recent upgrades > > On Thu, Dec 8, 2016 at 2:35 PM, Jason Price <[email protected]> wrote: >> I think we're going to need something a little more specific to go on. >> That is a mile of changes all at once. > > Yes: varnishlog, coffee, and a lot of patience. > >> Finding a single request that should be cached, but isn't and >> producing the varnish log for that request will probably help illuminate >> what's going on. > > There's currently no way to query the transaction log of a specific request: > https://github.com/varnishcache/varnish-cache/issues/2154 > > I'm just saying... > > Dridi > _______________________________________________ > varnish-misc mailing list > [email protected] > https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc -- Dag Haavi Finstad Software Developer | Varnish Software Mobile: +47 476 64 134 We Make Websites Fly! _______________________________________________ varnish-misc mailing list [email protected] https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
