[mythtv-users] Recording/playing back same file via NFS

[Brad DerManouelian]

On Aug 13, 2007, at 2:52 PM, Mark Lehrer wrote:

>
>> different recordings. Therefore, I have ruled out bandwidth as an
>> issue. The problem comes is when I try to view something that's
>> currently being recorded. It happen with both LiveTV and scheduled
>> recordings. It happens when I'm near the live TV point or if I start
>> watching something nearing the end of the recording. I get rather
>> frequent pauses in the video so that it is unwatchable. Like every
>> 3-5 seconds. This is even with the master backend recording SD and
>
>
> I had a similar problem (though not quite as frequent).  In my case,
> the write cache would fill up and write out every 30 seconds, freezing
> the video for an absolutely unbearable couple of seconds.
>
> Take a look at the config values /proc/sys/vm/dirty*
>
> If I remember correctly, I just had to turn the centisecs down so it
> wouldn't wait so long to write out the cache.  I'm sorry, power is out
> at my house or I could shell in and see the exact values I'm using -
> let me know if you're interested and I'll dig them up in a few hours.
>
> Once you find values you like, you can put them in /etc/sysctl.conf.
>
> Good luck,
> Mark

Ahh.. excellent advice and makes sense to what I am experiencing.  
Currently my values look like this:
[mythtv at mythtv2 vm]$ more dirty_*
::::::::::::::
dirty_background_ratio
::::::::::::::
10
::::::::::::::
dirty_expire_centisecs
::::::::::::::
2999
::::::::::::::
dirty_ratio
::::::::::::::
40
::::::::::::::
dirty_writeback_centisecs
::::::::::::::
499

I've never touched this stuff before. If you could take a peek at  
yours are and post back, I would really appreciate it.