Streaming development

Thomas SOUVIGNET thomas.souvignet at
Tue Sep 27 14:42:43 CEST 2011


I'm working for a company named SmartJog ( We 
currently are trying to build a file caching solution for HTTP servers 
streaming video and audio content. After having benchmarked several 
caching solutions we found out Varnish was the best performance-wise. 
Unfortunately, there seem to lack several features we would need and we 
ran into several issues.

Currently, our main problem is that while using a Varnish server in 
"streaming mode" and when a client connects to this server and asks for 
a file not cached yet, Varnish starts retrieving the file and sending it 
to the client while filling its cache. But if meanwhile a second client 
connects and ask for the same file, Varnish waits for having finished 
retrieving the whole file to start responding to this second client. Our 
plan at first is to patch this with the following behavior: if the 
second client asks for a file that is currently being cached but its 
caching isn't finished, we retrieve the file from the origin server or 
from the current cache if enough is filled and send it to the second 
client except this time we mark it as non-cacheable. Would you be 
interested by this patch ? If so, are we at least doing it the good way ?

Secondly, as we are going to need to do more developments on the 
streaming part of Varnish, would you be interested in SmartJog 
contributing to Varnish for this ?

Thanks in advance for your answers.


Thomas SOUVIGNET, R&E Engineer

SmartJog SAS - - A TDF Group Company
Office: 27, blvd Hippolyte Marques 94200 Ivry-sur-Seine - France EU
Phone: +33 (0)1 5868 6207

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