[mythtv-users] Are there any throttling features in Mythtv?

Cymen Vig cymenvig at gmail.com
Tue Feb 3 18:32:21 UTC 2009


On Tue, Feb 3, 2009 at 11:51 AM, Mike Perkins
<mikep at randomtraveller.org.uk> wrote:
> Kevin Kuphal wrote:
> I have also been keeping my mysql database on a different drive. I have two
> identical recording drives. I wanted to get to a situation of 1 drive (or
> more) per tuner, but the finances won't allow that yet. Actually, if money
> were no object, I'd have one mobo + drive per tuner, probably all in 1U rack
> cases, but that's not going to happen this side of hell freezing over, so I
> have to go with what I've got.

You don't say what your gear is but there may also be the option of
throwing better tuner/encoders at the problem. I'm down to only
recording over the air which works out great as ATSC is fairly
lightweight compared to the files I had coming out of my PVR-500 when
on cable. In both cases, the compression would be MPEG-2 but there is
a huge difference. Similarly, there are options now for encoding
analog to H.264/MPEG-4 which should also lower the bitrate (assuming
recording same content).

But even a fairly lightweight backend with a low end Core Duo or
equivalent AMD and inexpensive SATA drives should be able to handle
quite a few streams (assuming combined frontend/backend). It might be
the configuration of your hardware. Say you're recording four streams
and the resulting files are 8 GB/hr:

 8 GB x 4 = 32 GB / 60 = .533 GB / minute =~ 550 MB / minute = 9.2 MB / second

There will of course be more over head but assuming you're writing 4
streams and reading 1 most typical SATA drives should be able to
handle it without breaking a sweat. Now if you add in other processes
that are reading/writing large amounts of data (ie commflagging, etc)
then...

Cymen


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