[mythtv-users] Realtime commflagging....was: How many simultaneous recordings on one drive?

David Whyte david.whyte at gmail.com
Thu Sep 29 03:29:31 UTC 2011

On Thu, Sep 29, 2011 at 8:28 AM, Simon Hobson <linux at thehobsons.co.uk> wrote:
> Now I've got a machine dedicated to the backend, I've configured to
> start commflagging when a recording starts (only one job at the
> moment - need to experiment to see if two works well). The idea is
> that it can process the data as it's received, and so can work from
> what's already held in the OS cache and thus not add to the I/O load
> by reading a recording in after it's finished.

Is this really how realtime commflagging works?  If the data is being
processed as it is received, I am assuming you mean the data is read
off the tuner, buffered somewhere in memory and the commflagger
processes it then writes it to disk.

This raises two questions:
1) What if the commflagger can't keep up? How big is the buffer?
2) What if the commfalgger 'crashes', would the data never get stored to disk.

I am pretty sure that realtime commflagging is just another job that
is started at the same time as the recording starts (assuming there is
a spare job slot) but if I am wrong, could someone confirm?


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