[mythtv-users] Odd filespace issue

[Raymond Wagner]

On 10/1/2013 10:28 AM, Joseph Fry wrote:
>>> Just finally got the old girl running again last weekend with .26 (yeah,
>>> just in time for .27; I'll upgrade it this weekend), and aside from all
>>> the other problems I'm working, one really odd thing:
>>>
>>> I have watched it record to a file on one particular filesystem (XFS,
>>> freshly cleaned after replacing the mobo from a zorch), and while the file
>>> size goes up as expected, the free space on the volume as reported by
>>>
>>>   df -h
>>>
>>> doesn't change at *all*.  That seems very odd.  Can anyone think of a reason
>>> for that that I couldn't?  :-)  Checked the filename, and it was definitely
>>> the recording we thought it was supposed to me.
>>>
>>> Cheers,
>>> -- jra
>> Pre-Allocation?
> In addition to pre-allocation... you may also need to run a "sync"
> command to actually write the data to the drive; as it is likely
> recording to a memory buffer.

MythTV is already calling a sync one per second for each file it is 
writing to, specifically to prevent the production of a large memory 
buffer (and the consequences when the system tries to flush that large 
buffer).