[mythtv-users] please sanity check my new hardware

Steven Adeff adeffs.mythtv at gmail.com
Thu Apr 6 16:49:17 UTC 2006


On 4/6/06, Disconnect <mythtv at gotontheinter.net> wrote:
> On Thu, 06 Apr 2006, Steven Adeff did have cause to say:
>
> > On 4/6/06, Disconnect <mythtv at gotontheinter.net> wrote:
> > > Athlon XP 2500+ (1.8G) on an nforce2 board, raid5 (3 drives - 1 ata-100 on
> > > the onboard controller, 2 ata-100-in-sata-adapters on a SiL 3512 board) with
> > > a gig of ram.  Which might be fine for a dedicated box, but it was sluggish
> > > even before mythtv was put on it. (Its the general-purpose services and
> > > fileserver box.)
> >
> > That should be more than enough for a good mythbackend. Assuming its a
> > 5PCI board it would also give you room to expand to more tuners (say a
> > PVR500 and another HD tuner...). You don't mention the size of your
> > RAID5 array, but one would be perfect for a mutliple tuner HD setup.
> > You could archive to the 400GB drives (or get a 3rd and run those in a
> > RAID5 as well...). I assume "general-purpose services" mean something
> > along the lines of Apache, Samba, possibly FTP and email? Those
> > shouldn't add enough load overall to make much difference.
>
> It does quite a lot more than that. (16 domains worth of webserving, most
> with dynamic content, several hundred active email users, etc.)
>
> Right now, with tvtime stopped and myth idle, I've got:
>  12:15:46 up 8 days,  2:05,  6 users,  load average: 2.08, 1.78, 1.48
>
>              total       used       free     shared    buffers     cached
> Mem:       1036824    1018680      18144          0      16468     547252
> -/+ buffers/cache:     454960     581864
> Swap:      1992040     387188    1604852
>
> /dev/md4              457G  414G   21G  96% /
>
> The system is already loaded about as much as I want to let it get. (And,
> unfortunately, the bays are full at this point. So I can't add storage to it
> without trashing the array.) I did light up my recovery drive (ATA-100) as a
> non-raid independent disk for myth to use for storing video and such, but
> that didn't help (or at least, not in any major way).
> > > The biggest problem is playback. (And not filling my array with data that
> > > doesn't need to be there.) But even recording seems to have problems. I was
> > > thoroughly disappointed with the quality of the OTA show I had it tape last
> > > night (undersea adventures, off PBS) as it was full of glitches and
> > > artifacts. (It might be reception, I haven't gotten a chance to check yet.)
> > > Lower-bandwidth HD is passable, higher-bandwidth generally drags the system
> > > down so bad I have to log in and kill mythfrontend entirely. (For example,
> > > while I was testing WUSA was showing a basketball game in some insanely
> > > hidef format. Just tuning it in caused the play/hang/play/hang cycle to get
> > > so bad that remote inputs were processed 90-120 seconds late. Although live
> > > without myth worked better, it was still pretty unhappy.)
> >
> > Thats because the XP just isn't fast enough to keep up with decoding
> > the stream for writing to the harddrive and playback to your TV. My
> > Athlon64 3200+ can't playback 1080i and record off three HD tuners at
> > the same time either, its just not fast enough for that.
>
> > > I can play live hd with mplayer and such no problem (with the exceptions
> > > above), but as soon as myth gets involved it goes to hell. (Even the tivo
> > > svideo input gets stuttery and - until I get digital audio passthrough going
> > > - it desyncs due to the live-buffer "feature". So for now, tivo is handled
> > > by me ssh'ing in and starting tvtime and hd is live or - usually - just
> > > straight from the dtv receiver. And yes, editing the menus to add tvtime is
> > > on my list of to-dos.)
> >
> > Myth does a lot of things when it records that mplayer doesn't, which
> > adds to the required load handling.
>
> Right, and the biggest problem is that even prerecorded shows (which play
> fine on the mac, or even via mplayer in some cases) don't play back worth a
> darn in mythtv.
>
> > > That would involve 2 new computers. I agree it might be the right answer,
> > > but its not an answer I can do today..
> >
> > just one new computer and a little shuffling...
>
> The shuffling is going to have to be onto a new computer. (Although it would
> force me to get off my butt and better integrate the gig-e gear I got
> recently.)
>
> > I figure one of their small form factors and a small form factor
> > motherboard will be about the same price. You can even look at one of
> > the other microatx boards with XvMC capable onboard video. Since it
> > will only be a front end all it would need is video and audio out,
> > ethernet, and perhaps a DVD drive. Most of the Silverstone's come with
> > remote and LCD.
>
> Interesting designs. I'll see what I come up with today poking at those -
> might post an updated list.

Go with the Shuttle, as long as your fine with only having an HDTV
tuner then it looks fine. I'd still suggest an nvidia card, and you
could get away with a 3200+ which will let you playback 1080i while
recording. simultaneous comflagging would require a little more.

--
Steve


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