[mythtv-users] Master backend/storage, 1 or 2 machines?

Jim Minihane MythTV at minihane.tzo.com
Thu Aug 17 11:41:58 UTC 2006



-----Original Message-----
From: Brad Templeton <brad+myth at templetons.com>
To: Discussion about mythtv <mythtv-users at mythtv.org>
Date: Wed, 16 Aug 2006 14:04:34 -0700
Subject: Re: [mythtv-users] Master backend/storage, 1 or 2 machines?

> On Wed, Aug 16, 2006 at 03:27:40PM -0400, Steven Adeff wrote:
> > > > On 8/16/06, Jim Minihane <MythTV at minihane.tzo.com> wrote:
> > > > > I'm building a system with 2 slave backends (2 PVR-500s each, 8
> DirecTV
> > > > > D10-100s), one master backend and currently 2 frontends. The
> master and
> > > > > frontends have no decoders. I was going to use network storage
> via NFS
> > > > to my
> > > > > file server, but things have changed. The master is a 1.8GHz
> Compaq EVO.
> > > > > Would it be sufficient to serve as storage as well if I add
> eSATA
> > > > storage?
> > > > > My network is 100Mbps. I also have a second EVO 1.8GHz machine
> that
> > > > could be
> > > > > used as NAS, but I'd like to avoid that if possible. What would
> it take
> > > > for
> > > > > a machine to serve as master backend AND storage for an 8
> encoder
> > > > system?
> > > >
> > > > confused...
> 
> Seems like an unusual design.   Since a typical system that's on all
> the time consumes an average of about 100 watts, and that costs $110
> per year in California, it quickly becomes a lot simpler to just buy
> a nice large case and standard ATX 5-slot motherboard, and have just
> one backend with the 4 tuner cards, and then add as many disks as
> you like and a UPS (10 watts).
> 
> (Diskless computers, if that's what you plan, are less than 100 watts,
> but
> the disks just move somewhere else.)
> 
> Backends with wintv-pvr cards have effectively no CPU load for
> recording.
> Their only CPU load is niced commercial scanning or transcode.
> 
> I would have assumed the tunerless master backend is some other
> existing
> system, but you talk about it being diskless so I am not sure I
> understand.
> 
> I presume this is a system for a large dorm or commercial operation or
> something?  Hard to imagine even the largest family needing 8 tuners.
> 
> It's true if you have the two backends, you can handle one of them
> being down, which may be important here, but if the master goes down
> you are still hosed, unfortunately.   (If you were really eager you
> could recode MythTV to have redundant masters so any backend can switch
> to becoming the master if the master is down, as long as the sql
> database
> is still up, of course.)

Unusual? I guess. I need 8 PCI case slots just for the PVR-500s (4 for the
PVR-500s themselves, and 4 more for the secondary S-Video inputs). Then
there's the serial cards too (2 ports in each machine and a PCI card to
add 2 more to each machine). The master isn't diskless. Its internal HDD
would be for OS, Myth, etc. Just the Video partition would be external
(via NFS or eSATA) since the master case is just too small for multiple
drives. I already have a few much larger machines running anyway. The
electrical usage is not really an issue. This is for my home. I travel a
lot and my wife never has time to watch TV with kids, etc. So pretty much
anything we watch will be TiVo'd (oops, I mean Mythed). I'll want to use
PIP on the main TV downstairs. If my wife is watching something else, that
another tuner.

So...
Is my master "sturdy" enough to perform the tasks of a master, MySQL DB,
storing for 8 encoders, reading for 2-3 frontends, etc?





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