[mythtv-users] Comments sought on combined FE/BE box spec

R. G. Newbury newbury at mandamus.org
Tue Feb 2 21:25:51 UTC 2010


On 02/02/2010 10:47 AM, Michael PARKER wrote:

> 2) Forgive my ignorance, but what advantage would a separate 80GB OS disk give over a partitioned
> 2TB disk? At 3Gb/s and with 32MB of disk cache, I'm assuming the usual advantage of idependent drive
> accesses is no longer significant. Another disk is possible in the case, but I'm keen not to
> increase power consumption and noise further. I did think a solid state disk for the OS would be
> nice, provided frequently accessed stuff, swap etc. was put on the 2TB.

There are a number of main advantages to having a separate HD for the 
OS. 1) You can absolutely separate the video store from the OS. With a 
cron'd backup to the video disk, it does not matter what happens to the 
OS drive. You can replace it easily, if necessary. This means that the 
OS drive can fail, or the OS can fail and it is highly unlikely to take 
your video files AND your database with it. If you are paranoid about 
saving your video files, then raid the video disks, but don't bother 
with doing that to the OS drive.

2) You can optimize the video drive for dealing with video files. With 
tv recordings we have a few very large files. With an OS we have a LOT 
of very small files. No file system can deal with both of those as well 
as an optimized fs can. So, ext3 (or ext4) for the OS, and xfs (or jfs) 
for the video drive (especially allocsize=xx where xx is something like 
512M).
3) The OS footprint on a pure mythbox is quite small and can be under 
8G. It is quite possible to run a mythbox in 16G....meaning that, for 
example, a 16G SSD is usable, and not really any more expensive than the 
smallest rotating disk you can buy. But has lower heat,power and sound 
levels. (The video drive is set to spin-down, of course). (A recent 
local ad had a 16G eSata (ssd) drive for $61.00 (uses USB for power and 
eSata for transport. 8G for $30.00).


> 3) My originally spec'ed mainboard was a Gigabyte GA-MA785GMT-UD2H. After much agonising over ATI vs
> Nvidia GPUs, I decided to go for a VDPAU-capable onboard Nvidia GPU. Since the Gigabyte board had
> onboard ATI graphics and a passively cooled PCIex16 would almost certainly not fit alongside two
> populated PCI slots, I decided to go for the ASUS board and do without DDR3 support. A fan-cooled
> graphics card is a possibility but the additional power and fan noise don't appeal much.

Since you are buying new, go for a better nvidia gpu. I have an Asus 
P5L-MX motherboard which carries a Geforce 9300 chipset which easily 
does HD. I am not sure that an 8200 will (an 8300 is supposed to be 
equal to the 9300, but I am not sure).

Geoff

         Please let me know if anything I say offends you.
          I may wish to offend you again in the future.

          Tux says: "Be regular. Eat cron flakes."


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