[mythtv-users] Diskless

[Peter A. Daly]

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.

http://www.mythpvr.com/mythtv/distribution/minimyth/compact-flash-install.html

I'm happy with my ME6000 based system.

-Pete
http://www.mythpvr.com

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
> QUIET".
> >
> > 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
> me.
> 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.
>
>
> Cheers,
>
> Johan.
>
>
> > --- End Original ---
> >
> > Hi Rich,
> >
> > If your network is 100 Megabit-switched, you should have nothing to
> worry
> > 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
> of
> > data.  Well, we measure data (disk size) in Bytes (big B), but network
> speed
> > 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
> sustain
> > 20Mb/sec (2.5 * 8, where there are 8 bits in a Byte), which is a cinch
> for
> > 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
> 80Mb/s
> > receive at the same time.
> >
> > So, the bandwidth is there.  Since the worst you can likely do is stream
> an
> > HDTV from each frontend, the only consideration is the common network
> > segment, which is your backend to the network switch.  Say, for example,
> you
> > 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
> to
> > 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
> from
> > 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),
> so
> > 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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