On Fri, 2013-08-09 at 19:36 +0200, daf@debian.org wrote: > On Fri, Aug 09, 2013 at 12:26:49AM +0200, Ben Hutchings wrote: > > On Thu, 2013-08-08 at 21:07 +0200, Wouter Verhelst wrote: > > > On 08-08-13 19:59, Axel Beckert wrote: > > > > Hi, > > > > > > > > On Thu, Aug 08, 2013 at 05:33:11PM +0200, Holger Levsen wrote: > > > >>> What is the bandwidth at the site like? > > > >> > > > >> 100mbit symetric, afaik. cc: abe@d.o to confirm > > > > > > > > That's what I have been told. But it seems to be more. > > > > > > > > Over a long time (mirror sync) I got 33 MB/s easily and peaks up to > > > > 126 MB/s which smells suspiciously like the 1 GBit/s others were > > > > mentioning. > > > > > > Maybe that just means that the SLA is 100mbit, but that we can use more > > > if the bandwidth is available? > > > > In any case, I would not suggest we rely on being able to use more than > > a fraction of that bandwidth for video streams. > > > > Daf, the way we've done streaming at DebConf so far (7 years now?) is > > shown in: > > http://anonscm.debian.org/gitweb/?p=debconf-video/package.git;a=blob;f=doc/network-debconf.png;h=f958a0b472c1150df3e6b3feefdcb2429c0050bd;hb=a1522ac272ccd3f211cec9e806a0df4f197252a5 > > Each stream is sent to a single internal server (localstream1). There > > is a single external relay (krusty) pulling from localstream1, and then > > multiple additional relays pulling from krusty. Thus, streams are > > available to internal and external viewers without multiple copies being > > sent over the WAN link. > > > > I'm still unclear on whether you can use Icecast for the subtitled WebM > > streams. If so, then a similar arrangement should be possible. Ideally > > we could use the same set of relay servers. > > We don't produce subtitled streams; any annotations are distributed > out of band. (In the future I expect we will support some combination > of WebVTT and SRT export.) Right, but the point is, you do produce your own streams. [...] > If bandwidth usage is a concern, we could try to work out a setup that > only involves a single upload per stream. > > Asa a reference, looking at some of our output from OHM, our WebMs > were encoded at approximately 241kbps, or 1.7MiBytes per minute. I > think this means that at 100mbit, 4 viewers would saturate the uplink. [...] 400 :-) I think we get of the order of 100 viewers outside, though I can't find recent figures. So that's probably enough. However, I don't know whether we can sustain this rate, or whether the network administrators would want to open up the firewall to allow connections to an internal server for everywhere. Generally we will have fewer internal than external stream viewers. So if you can only use a single streaming server or if it's prohibitively difficult to use relays, the server should be external. Ben. -- Ben Hutchings I say we take off; nuke the site from orbit. It's the only way to be sure.
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