connor.walls at skillpages
Nov 2, 2011, 3:15 AM
Post #3 of 3
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RE: Question about varnishstat and hitrate
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Great, thanks very much!
-Connor
From: Stig Bakken [mailto:stig [at] zedge]
Sent: 02 November 2011 10:15
To: Connor Walls
Cc: varnish-misc [at] varnish-cache
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 <connor.walls [at] skillpages<mailto:connor.walls [at] skillpages>> 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
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--
Stig Bakken
CTO, Zedge.net - free your phone!
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