[mythtv-users] Opinion on a P4 Backend // HDD Throughput

[Jeff Holicky]

Hi all, I am looking at implementing a Myth system at home - with up to
five frontends when all is said and done.  We rent a dual tuner PVR and
also have a cable box - limited to a small harddrive and no real
archival system nor easy way of playing back multiple formats has helped
with my decision to create a myth system.  Definitely looking at at
least 3-4 SD (standard def) tuners initially [PVR 150x4] (later HD) and
would like some feedback on my initial setup and to realistically set my
expectations.  

Today I want to have the BE act as an occasional FE with plans down the
road to make it a BE only box (if possible).  Running 100Mbit CAT5 cable
with the goal to run 1000Mbit CAT6 and/or try wireless.  Perhaps in a
year or two move to HD by swapping out 2SD tuners.  Start off with two
dedicated FE's.

Don't want DVD players on each FE - want to stream archive content off a
NAS device.   (1 or 2TB drive; 100 or Gigabit)

Q1) I am not clear on the ability to do multiple streaming AND recording
simultaneously.  Someone I spoke to felt my ability to do both may be a
problem due to bottleneck issues at the HDD.  Assuming a model of 4
tuners - 1 streaming; 3 recording OR 2 streaming 2 recording; OR 3
streaming 1 recording -- are all these possible?  

Q2) Then there is that "commercial skipping" process - not sure if that
still needs to be processed off peak times or not.

Q3) Plus is there a difference between 
a) Streaming program A; recording program B
OR
b) Recording program A and streaming program A (few minutes offset)

Q4) I have noticed some that already have 2HD and 2SD tuners in one box
- but then if they are only recording (on one or more), then there may
not be any problems.

Q5) My friend suggested the issue was less CPU and more HDD - and maybe
if I was running a 10K drive - MAYBE I would be okay -- and/or if I
mixed in a RAID system of sorts to balance the load.

Q6) The other thought is adding in a second backend eventually - not
sure if that is a no brainer or exponentially more complex and not
desirable.  

Q7) I assume playing an archived movie off the NAS is merely networking
between the NAS and FE - and cabling and less BE - please confirm.

*Config*
Part of my plan having 4 tuners hit a road block with most MOBOs today
supporting only 3 PCI cards (Thanks to Brian for pointing that out).  I
found one so far - but also I remembered I have a P4.  I feel if the P4
works, based on set expectations, then I can buy a nice higher end
system as a desktop replacement.  Worse case later turn the P4 into a
FE.

Currently I have:
- ASUS P4P800 MOBO (enough PCI slots); 
- Intel P4 2.8Ghz w/HT; 
- 2GB RAM; 
- 450W P/S
- ATI All-in-Blunder 9600 of which I would only use for controlling the
video out (if possible)
- ATA 133 HDD - I have several 120GB 7200RPM drives at my disposal ..
see below 

MOBO supports:

- 2xUDMA 100 (4drives)
- 2xSATA w/RAID 0

RAID CONTROLLER
- 2xUDMA 133 (4drives)
- RAID 0, 1, 0+1, RAID JBOD

Moving to SATA doesn't seem to be that much of an option with this MOBO
- I figure I am just as well with the RAID controller (I use ATA 133
today with 4 drives).  


If my ideas of streaming and recording are not far fetched - but my
config is a little dated, if possible, please point me in a direction -
need a MOBO that has X; or a minimum CPU Y etc.
Just want some input - a "that dog will or won't hunt" big picture
response.  

thanks all & cheers!
jeff