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

[Alex Butcher]

On Mon, 14 Mar 2011, Neil Cooper 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.

I wouldn't be so sure. A DVB-T2 multiplex (carrying probably 4 channels or
more) is about 35Mbit/s, whilst a modern consumer SATA disc should do about
120Mbyte/s at the rim and still about 60Mbyte/s at the hub.  Even at the
hub, that's 480Mbit/s, or enough to cope with upto 13 complete DVB-T
multiplexes!

Seek time might be an issue, as will be CPU/GPU grunt for the decoding. 
Using ionice on the advert detection/transcoding processes to give them the
lowest IO priority is probably a good idea, as is boosting mythbackend,
mysql and mythfrontend's IO priority a bit.

Best Regards,
Alex