Peter A. Daly
petedaly at gmail.com
Fri Feb 2 15:46:21 UTC 2007
I've updated my page on how to boot MiniMyth from compact flash if you want
to go the MiniMyth route but don't want to mess with the network boot.
I'm happy with my ME6000 based system.
On 2/2/07, Johan Braeken <list.mythtv.users at centerpoint.be> wrote:
> Quoting Richard Stanaford <rstanaford at gmail.com>:
> > --- Original Message ---
> > I came across the diskless how-to on the Wiki and, while I have the
> > entire infrastructure in place (I build both windows and Linux boxes via
> > PXE booting), I immediately thought "hey, that would definitely be
> > However, the question that goes unanswered in the wiki is about
> > performance. Since the entire system is loading and running off of the
> > network (I've got cat-5 wired) *and* mythtv is also going over that same
> > network, doesn't that beat up on the performance? Especially since swap
> > would also be on an NFS mounted volume...
> > I'd be interested to hear about people's experiences with MythTV and a
> > diskless frontend to see if it would be a viable configuration or if it
> > is just a pipe dream..
> I have a MiniMyth frontend.
> It is booting with PXE and running entirely in RAM (512Mb, no swap)
> Videos and Music are accessed via NFS.
> Working perfectly!
> I even have all my DVDs in iso format on the server so I can watch them.
> I also run LTSP on the same network and network speed is not an issue for
> Even when doing massive filetransfers, close to the maximum
> theoretical network speed, Mythtv keeps running smoothly.
> I have to say I have a Cisco switch, which will probably perform
> better than a "entry-level" model. But, even then, I would not expect
> problems due to the slow network speeds actually required as explained
> below by another poster.
> So I would say, running MythTV, even with multiple clients, over the
> network is not a problem at all.
> > --- End Original ---
> > Hi Rich,
> > If your network is 100 Megabit-switched, you should have nothing to
> > about, even if you want to stream HDTV. Consider that under most
> > configurations, HDTV encoding will commit up to 9GB per hour of
> video. Nine
> > gigabytes (or approx 9000MB) per hour is approx 150MB/min or 2.5MB/sec
> > data. Well, we measure data (disk size) in Bytes (big B), but network
> > is usually measured in bits (or bits per second, little b). So, in
> order to
> > smoothly stream HDTV to your frontend, you would need to be able to
> > 20Mb/sec (2.5 * 8, where there are 8 bits in a Byte), which is a cinch
> > 100Mb-switched, assuming everything is running at full duplex. When
> > transferring file between my machines, my network routinely sustains
> > 80Mb/s. And since it's full duplex, that means 80Mb/s transmit and
> > receive at the same time.
> > So, the bandwidth is there. Since the worst you can likely do is stream
> > HDTV from each frontend, the only consideration is the common network
> > segment, which is your backend to the network switch. Say, for example,
> > wished to stream three HDTV streams to three different frontends. Each
> > frontend would put 20Mb/s on its own link to the switch which would
> > aggregate to about 60Mb/s throughput for your server. You're not likely
> > ever do that, but I wanted to use that as an extreme example.
> > With a sufficient amount of RAM, you are not likely to have to NFS swap
> > the frontends, even with 256MB of memory, especially if you are doing
> > hardware decoding. The output from come through the network interface,
> > across the bus to the decode hardware of your video card (or chipset),
> > there's really nothing to buffer. Unless you have stuff running on the
> > frontend box other than just MythTV, there should be nothing to swap
> > either. But even if it had to, your network would have to be taxed
> > virtually to its "knees" for you to notice it.
> > I hope this helps a little.
> > -Rich.
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> mythtv-users at mythtv.org
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