[mythtv-users] Build for dual HD recordings - also is PSU enough/too much

[Tom Bongiorno]

On Mon, Mar 14, 2011 at 2:37 PM, Neil Cooper <neilcoo at yahoo.co.uk> wrote:
>
> You need to consider the worst case situation of recording 2 HD shows concurrently, during playback of another HD show while maybe also doing advert detection/transcoding in the background and remaining responsive to other activity such as input from a remote and/or slave frontends.
> One harddrive isn't going to cut it. It will definately be the bottleneck.

Is this really true?  In prime time I am often recording 3 to 4 HD
shows and watching 1 to 2 from one hard drive with no problem.  My
hard drive is a regular 7200RPM 1.5TB Seagate.  I am also on a gigabit
network.

Lets say we have 5 five stream going in either direction at worst case
20Mbps each.  That is 100Mbps or 12.5MBps.  That doesn't seem high for
a drive.  I have Comcast, and they don't broadcast anywhere near
20Mb/s per stream.  It has been a while since I checked, but if I
remember correctly, they broadcast in the 8-12Mbps range for HD.  If
they average 10Mbps per stream, then that is 50Mbps or 6.25MBps worth
of reads and write to the hard drive.

Correct me if I am wrong because I could be doing some bad math.