[mythtv-users] ATA RAID Question

maarten van den Berg mythtv at ultratux.org
Tue Mar 16 07:48:16 EST 2004

On Tuesday 16 March 2004 12:12, David wrote:
> and aren't 5400 drives a *lot* cooler?
> I 've made the mistake of buying a 7200 SATA disk and they run hot!
> Which means I need fans which means noise...

I fully concur.  For instance, I have a home fileserver built with 6 disks in 
software raid5 configuration. I settled for 5400 rpm disks after I realised 
that _whatever_ I did, the home 100Mbit LAN would be the bottleneck anyway.
Any reasonably modern drive could sustain 10Mbyte/s and that is the 
theoretical top speed of 100Mbit ethernet which is never reached in practice.

The only two instances in which that decision would be wrong in hindsight 
would conceivably be
A) when I would migrate to gigabit LAN
B) When I would run I/O-demanding apps on the fileserver itself

Well, scenario A is very unlikely because I do not need it and by the time I 
would consider gigabit LAN I would laugh at the 0,4 TB capacity of the 
fileserver and build a new one with, like, 2 TB diskspace or so  :-)
Scenario B does sometimes happen but its invariably a non-time critical job, 
typically some cronjob or such.

Not that my six-disk two-120mm-fan system is _quiet_ though, far from it ;-) 
But hey, it's a fileserver; it is stashed somewhere out of hearing-distance.

> Luckily this all got kicked off because the wife said she wanted a PVR
> and offered to donate her PC as a test bed ;)
> What we're doing now is bodging it together in her PC (which we'll
> restore at some point) and then once it's all going we'll buy a
> mobo/case etc for a dedicated machine.
> I'm now thinking lower end CPU (but not *too* low) with passive cooling,
> variable speed psu, 5400rpm disks (probably multiples), old VGA card (I
> may try the VGA/RGB hack at some point) and a sound card with SPDIF.

I decided on the opposite; an athlon 2600+ and a variable speed PSU which 
sports a 120mm fan mounted horizontally as an intake-fan (AOpen PSU 
A0350-12APNF which I can't locate on the web but it is similar to this one 
but with a fan speed control): 
Since it has real efficient airflow (look at the size of the holes in the 
outlet) and a 120mm fan is _real_ powerful I think it just may serve as 
cooling for the entire system. So I plan to investigate whether I can 
passive-cool the (high-powered) athlon, possibly by using one of those Zalman 
coolers (see  http://www.zalman.co.kr/images/0212/6100alcu3-b.gif )

I'm obviously not sure if that will work.  It is a risk, but one I'm willing 
to take...  very good monitoring while doing tryouts is essential of course.

I might have another, entirely unrelated, tip for people struggling with TV 
outputs and the like:  I bought a beamer a few months ago, and a beamer 
almost always has a VGA input in addtion to Svideo/composite.  So I just 
connect to it directly without any hassle.  
Not to say that a beamer is a viable choice for anybody but please stop and 
think about it a bit: I paid about US$ 1100 (1000 euros) which is a lot of 
money but still somewhat affordable. And you can probably save on the cost of 
an expensive "home cinema" plasma/LCD TV and on the cost of a PVR350 card as 
well. And of course, combining a MythTV setup with a beamer scores you very 
high points for the Wife-Acceptance-Factor and bonus nerd points as well...  

One point to realize though is that a beamer uses a _very_ expensive lamp and 
you have to replace it every 1000-1500 hours. But that still can go a long 
way, if you watch 3 hours a day every day it's only one year but if you use 
it moderately it will go 2 or 3 years with one lamp.  A lamp costs ~$500(!).
The beamer I bought is the Iiyama LPX-100, just for reference.


> malcolm wrote:
> >You really don't need such powerful drives for mythtv.  I have a PVR-350
> >(using tv out) and a PVR-250.  I can capture two shows at once and view a
> >pre-recorded show (or watch one of the shows currently been recorded) at
> > the same time and my ata33 5400rpm drive (not 133 but just 33) humms
> > right along with not to much stress.
> >
> >If you think about it the PVR-350 or 250 with Myth's default settings
> > writes 2.2Gigs an hour.  So recording 2 shows at once: Do you think your
> > ata33 drive can handle writing 4.4Gigs in an hour?  Sure of course it
> > can.

Yes of course I'm sure it's the red cable. I guarante[^%!/+)F#0c|'NO CARRIER

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