[vdr] Re: complicated hardware setup

[Oliver Brandt <oliver_mlisten@gmx.de>]

Hi,

Thanks for this very helpful answer!

> > > Should use 1000Base-T for the server (one TS-stream from the server has
> > > about 25-40 MBit/s).
> > 
> > This means I'll need a 1000Base-T switch, too. I looked at alternate and
> > they are very expensive (300 Euro). I belive there are others avalible
> > with just one 1000Base-T port but I could not find any and so I don't
> > know how expensive they are.
> 
> Much cheaper. You can also look at ebay. Currently you often get 6 or 12
> month old high-end switches for low prices because of the much
> insolvencies in Germany.

I looked at ebay last night, too. And getting a switch and stuff there
seems to be a rather affordable way. There really is a lot of high end
equipment out there right now.

> > Anyway, talking about 1000Base-T the
> > PCI-bus poped into my head. Is a 32bit PCI engought for the 1000Base-T,
> > one Nexus, three Novas and the IDE-Raid. Seams to me this could be the
> > next problem (German: Flaschenhals). Do you think I need a 64bit PCI?
> > Because then we are talking serious money, The 64bit Mainboard, 64bit
> > 1000Base-T and switch, 64bit IDE-controler (could not find one on alternate)... Do
> > you think 64bit is necessary?
> > Would a complete set of Nova cards instead of the Nexus make any
> > difference on the server cpu and bus load?
> > How fast of a cpu do I need in the server and how much Ram?
> 
> I'm maintaining a server with 3 budgets, DVD-R(W), one HDD and
> 1000Base-T running NFS, NIS, DNS, vdr-streamdev and Firewall.
> 
> It's a simple 32-bit system with Celeron1100, 768 MB RAM.
Sound good. I that much ram needed?

> If I remind well PCI has a throughput of about 800 MBit/s.
> Running 4 DVB-S recording will consume about 120 MBit/s, the 1000Base-T
> NIC (all have cache and own µProcessor) will consume less than 240
> MBit/s.
Those actual numbers really help!

> Onboard Raid-controllers are good for nothing. You'll only scare the PCI
> when you invest at least 500 Euros in an IDE-Raid controller.

Actually I was thinking about having the kernel do software raid 5 for
redundancy. I've read that the preformens of the cheap raidcontrolers is
worse then if you just have the kernel do it all by itself. A friend of
mine is running this type of setup at the moment and is pretty pleased.
Now that I know what preformance I need (see below) I'll check if the
thoughput on his machine would be enought.

> > What does the cluster-plugin do? Does it translate the viedo-input into
> > mpeg1 or mpeg2 or something compleately different to send it over the
> > network?
> 
> The A/V (e.g. DivX) is sent from the client to the server, which
> transcodes into MPEG1 and sends back the stream.
MPEG1, so that's where the traffic is comming from...
> 
> > By using a dxr3 I understand those weak clients won't need the
> > cluster-plugin for playing the DVB-stream delivered by the
> > streaming-plugin and for DVDs. Do I need it for playing divX or can
> > I go totally without the cluster-plugin in case of a
> > dxr3.
> 
> You need something like a Celeron500 (maybe 400 MHz could work) to
> transcode from DivX to MPEG1. The passive cooled VIAs are to weak to do
> this. Then you need the cluster-plugin.

Can the clusterplugin be configured, so that it is only used if the
stream is not MPEG1 or MPEG2? In this case dvds, video cds and the DVB
signal would be decoded locally and only stuff like DivX would put high
traffic to the network and use the server resources. I'm kind of
thinking about building a diskles client that will work without a server
by booting from a compact flash or linux-bios. If the server is not
avalible will it still function without the user having to take any
actions (ofcourse then I'd have to put a DVB-card into the client). What
I'm worried about is that if the server fails, my dad can't even watch
tv or dvds anymore and I live over 1000km away from him, so I can't just
drive over and fix it. Anyway, if I mount my videofolder over NFS, have
the client cache the files for timeshift over NFS and activate the
cluster plugin will loosing the connection to the server just affect
those function or won't I even be able to watch a DVD and tv (ofcourse
no timeshift).

Thank you very much again for helping me get on the way. Giving me the
specific informations with detailed numbers (Mbits...) and telling me
about your own system really helped. I feel like I'm starting to get to
the point where I can start buing the first hardware pices and start to
experiment my self without risking to buy somthing totally wrong.

Cu
	Oliver


-- 
Info:
To unsubscribe send a mail to ecartis@linuxtv.org with "unsubscribe vdr" as subject.