VideoCache

Double Bandwith

by till79 on 3 May 2010

Hi
I have some strange Peaks in my server´s bandwith usage: when a user starts watching a youtube-video the input bandwith from ISP is twice high than the output bandwith to user. It seems that user´s browser bypassing videocache and loads directly (but through videocache). Videocache starts an own download too and stores the video in his cache. Videocache caches properly and serves right when a video is requested for a second time.
Double-bandwith-phenomena comes only when requesting new videos.

Is that normal?

Every video is requested sometimes for 3-4 times for one user request.
Logfile:
http://pastebin.com/SrfsFS21

So it´s not really saving bandwith...

Videocache 1.9.4 was installed with the installation-guide from this website. No own changes of ACL or something - and no forward-proxy. (OS: OpenSuse 11.2)

Do you have an idea to solve this?
Thanks for help!
Till

6 Answers

by Kulbir Saini on 6 May 2010

Hi!

The video is not downloaded everytime you see a URL_HIT line in the videocache log. A video is downloaded and cached by videocache only once if its not there in the cache already.

Several URL_HIT lines are because of the several request sent from youtube video page whenever user browses a video. Check corresponding squid access.log entries and you'll see that it also has several entries for the same video.

There is an option hit_threshold in videocache.conf to tweak this. Please have a look at that.

Thank You!

by Anonymous on 21 Dec 2011

Yes , I totaly agree with till 79 , video cache is not saving bandwidth at all , cause it's downloading every new video with the max speed available , and we all know that there is always new videos !!!
lets say a network of 50Mbps max bandwidth , we can easily see that videocache is eating 20Mbps or more for downloading and saving the videos in the cache drives , inspite of the limited user speed .
lets say a 512kbps download limit user is viewing youtube video without video cache , the max bandwidth that video will take is 512kbps , but with videocache it may reach > 2Mbps or more !!
there should be a solution for this old problem so that the videocache become a real bandwidth saver instead of bandwidth predator !!!

by Kulbir Saini on 21 Dec 2011

Hi Samsoft,

You are using version 1.9.2 which is probably 2 or more years old. Please don't judge the current version based on your experience with an age old version. Videocache has come a long way since then and we addressed this issue long back. Please use the latest version and share you experience :-)

Thank You!

by Anonymous on 21 Dec 2011

Hi

Admin you are correct , i sent you an email requesting WU details , i need to send payment today please ..

by FragtioN on 28 Feb 2012

Hi there,

I would like to contact you with regards to my interest in purchasing Videocache

However, there's one thing I've noticed in the forums which has me concerned: Apparently v1.9.9 still, new videos are acquired TWICE (double) from YouTube. In other words, if hit_threshold = 1, and the video is accessed for the first time, videocache will download the video to cache using a different thread to the traffic flowing to the end user. I'm using this in a low-user environment, and can't see the profit of video caching if the hit rate is lower than the likelihood of hitting a new video. It does not seem like this product will save me if it's doing twice the bandwidth. Is there any way to prevent the double-download problem? The example on http://wiki.squid-cache.org/ConfigExamples/DynamicContent/YouTube/Discussion is very incomplete compared to your product, however it does not face this problem.

Regards

by Kulbir Saini on 2 Mar 2012

Hi,

You are right. hit_threshold correct this issue only to a limited extent. We are getting rid of this issues from version 2.0.0 which is coming out very soon. Stay tuned for updates.

Thank You!

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