[mythtv-users] Howto prevent MythTV flushing/Syncing disk writes (LiveTV/Recordings)

[David Rees]

On Tue, Mar 18, 2008 at 6:09 AM, Albert Graham <agraham at g-b.net> wrote:
> Does anyone know how to prevent MythTV from flushing/syncing every
> single write request when watching LiveTV or  recording something.
>
> My machine has lots of memory and very large fast disks, so I would
> prefer writes to occur in much larger chunks and a lot less often,
> rather than every 3 or so MB.

Yes, as David Brodbeck mentioned, MythTV explicitly syncs video data to
disk every 250ms or so because "back in the day" some systems did
encounter hiccups when letting the OS flush data out to disk as it saw
fit. In some cases the amount of time it took to flush data to disk
took to long so this would cause playback to hiccup as the disk was
too busy writing (and not enough video was buffered to make up for it)
or recordings to hiccup as the disk writing process interrupted the
read process.

I also would prefer to let the data get flushed out automatically as
this would reduce the constant clatter of the disks. Or at least make
the sync interval configurable.

If you want to fix this, you're going to have to dig into the source code.

-Dave