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From "Muhammad Faisal" <>
Subject High Upstream Utilization Background Fetch Plugin behavior
Date Wed, 16 Mar 2016 19:13:27 GMT
After more than two months of testing and great support from entire ATS 
team, finally we have integrated ATS in production scenario as 
transparent caching . Currently we have put limited traffic to it approx 
200mbps (1k plus users). After putting actual load on the server i'm 
observing the upstream utilization has been increased. Last stats that i 
have viewed are 130Mbps (upstream) and 41.6Mbps (to clients) so there is 
negative impact of caching instead.

It is worth mentioning that I have used background fetch plugin to cache 
range requests (to improve cache performance specially streaming). The 
max object size currently is set to zero. During testing I have observed 
when downloading a large file the ATS were starting object download on 
available upstream capacity. The large file like ISO of 600 MB takes 
lots of bandwidth to fill the object while delivering to the user 
according to allocated speed on next object hit however the object was 
delivered from the cache.

I production scenario the above behavior is causing increased upstream 
utilization while the hit probability on larger objects are rare.

I need experts opinion to improve traffic saving. What comes to my mind 

- Set Max object size to 100 or 200 MB
- Keep using background_fill plugin and exclude the larger objects (max 
object size)
- How to exclude larger files to being background fill above e.g 200Mbps

Below are my background fill configs:

exclude Content -Length < 1000  (this is to exclude small object less 
than 1000 bytes?)
include Content-Type video/mp4
exclude Content-Type text
include Content-Type video/quicktime
include Content-Type video/3gpp
include Content-Type application/octet-stream


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