Great, thanks very much! -Connor
From: Stig Bakken [mailto:[email protected]] Sent: 02 November 2011 10:15 To: Connor Walls Cc: [email protected] Subject: Re: Question about varnishstat and hitrate Varnish's cache hit rate is a percentage of hits among requests that went through vcl_lookup, not all requests. - Stig On Wed, Nov 2, 2011 at 10:53 AM, Connor Walls <[email protected]<mailto:[email protected]>> wrote: Hi, I had a question about the numbers generated in varnishstat. Looking at the current hitrate average for one of our boxes is giving an average of 0.4833 for the last 1000 requests, and the hitrate is in and around this number on all of our varnish boxes. We are also recording the output of varnishlog to a file, including a “X-Cache” header, as per this article: https://www.varnish-cache.org/trac/wiki/VCLExampleHitMissHeader. Now, what I’m curious about is whenever I look at the responses that have been logged, <5% of them are being served from the cache, which is at odds with the 48% that varnishstat is reporting. Is the hitrate average only taking into account pages that are passed, and not pages that are fetched? Why is there such a discrepancy between the two values? Here’s a sample output from varnishstat, if it helps explain things better. 4+18:04:37 domU-12-31-39-10-74-A8 Hitrate ratio: 10 100 1000 Hitrate avg: 0.3646 0.4249 0.4833 1528600 3.96 3.72 Client connections accepted 10346326 23.77 25.19 Client requests received 5244804 0.99 12.77 Cache hits 9509 0.00 0.02 Cache hits for pass 147772 0.00 0.36 Cache misses 22490 0.00 0.05 Backend conn. success 4731723 21.79 11.52 Backend conn. reuses 12459 0.00 0.03 Backend conn. was closed 4744236 19.81 11.55 Backend conn. recycles 9505 0.00 0.02 Fetch head 4727908 20.80 11.51 Fetch with Length 1751 0.00 0.00 Fetch chunked 422 . . N struct sess_mem 96 . . N struct sess 4104 . . N struct object 4148 . . N struct objectcore 4115 . . N struct objecthead 48 . . N struct vbe_conn 53 . . N worker threads 7788 0.00 0.02 N worker threads created 0 0.00 0.00 N queued work requests 32999 0.00 0.08 N overflowed work requests 1 . . N backends 136098 . . N expired objects 397731 . . N LRU moved objects 8861590 17.82 21.58 Objects sent with write 1528600 3.96 3.72 Total Sessions 10346326 23.77 25.19 Total Requests 4600511 20.80 11.20 Total pass 4744331 20.80 11.55 Total fetch 5613543692<tel:5613543692> 14549.86 13669.00 Total header bytes 50230527274 64650.96 122311.52 Total body bytes 398864 1.98 0.97 Session Closed 1 0.00 0.00 Session Pipeline 9989106 21.79 24.32 Session Linger 4717398 17.82 11.49 Session herd 731094771 2065.68 1780.22 SHM records 29558086 95.06 71.97 SHM writes 14131 0.00 0.03 SHM MTX contention 353 0.00 0.00 SHM cycles through buffer 3518804 16.83 8.57 SMA allocator requests 8184 . . SMA outstanding allocations 46354320 . . SMA outstanding bytes 12051521527 . . SMA bytes allocated 12005167207 . . SMA bytes free 357190 1.98 0.87 SMS allocator requests 0 . . SMS outstanding allocations 0 . . SMS outstanding bytes 135529138 . . SMS bytes allocated 135529138 . . SMS bytes freed 4744578 20.80 11.55 Backend requests made 1 0.00 0.00 N vcl total 1 0.00 0.00 N vcl available 240460 . . N total active purges 353239 1.98 0.86 N new purges added 112779 0.99 0.27 N old purges deleted 510753 0.99 1.24 N objects tested 32284561 412.94 78.61 N regexps tested against 155686 0.99 0.38 N duplicate purges removed Thanks for any help, Connor Walls _______________________________________________ varnish-misc mailing list [email protected]<mailto:[email protected]> https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc -- Stig Bakken CTO, Zedge.net - free your phone!
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