[mythtv-users] Delete files slowly

[Greg Oliver]

On Mon, Jan 25, 2010 at 11:31 PM, Michael T. Dean
<mtdean at thirdcontact.com> wrote:
> On 01/25/2010 08:32 PM, Greg Oliver wrote:
>> I just noticed that while I have the setting to delete files slowly,
>> and recording, it records faster than it deletes.
>>
>> Is there logic in this setting, or can I assume that it will always
>> delete slower than 19mb/s (1 tuner)..  I guess ultimately I would hate
>> to have frame loss because it is clearing disk space too slowly, but I
>> am not familiar with the logic.  It may very well delete much faster
>> as the available space gets lower, etc..
>>
>
> Greg,
>
> It turns out that we used to have a minimum truncate rate of 8MiB/sec
> and would use that value or 120% the max recording bitrate (combined max
> bitrate of all cards), whichever was higher.  Before 0.21 was released,
> we removed the minimum truncate rate, so now do 120% ATSC max bitrate *
> number of cards (basically 2.78MiB/sec/card (including "virtual" cards
> for multirec)).
>
> After some discussion on IRC, we may re-institute the minimum truncate
> rate.  I plan to do some tests using different values for the truncate
> rate (from the above 2.78MiB/sec (for the "minimal" one-card system) to
> 4MiB/sec to 8MiB/sec) and see if it has an effect on
> http://svn.mythtv.org/trac/ticket/7315 (per discussion at and after
> http://www.gossamer-threads.com/lists/mythtv/dev/416521#416521 ).  If
> any of the values "fixes" #7315, I'll definitely institute a hard floor
> higher than the current.

Well, since my "proof of concept" machine is kind of puny (revo 1600),
using the entire disk for /, and 1gB for /home - could that play into
it as well.  I only have recurring recordings set for Monday nights
(24, heroes, house, etc...) to test things.  BUT - I have also copied
a few of my ripped DVDs to it as well.  (Never restarting the BE/FE
combo)..

> I won't be home until later this week, but if any enterprising users
> want to run some tests for me, please feel free.  You can simply
> hard-code values for min_tps at
> http://svn.mythtv.org/trac/browser/trunk/mythtv/programs/mythbackend/mainserver.cpp#L1915
> , i.e.:

I've been a happy *buntu user (until now) for a couple of years.  My
new job (moved from networking to systems) made it a pain to work on
my own machines fulltime, so I went the easy route.  I think I am
going to have to go back to gentoo for mythtv though...

> const size_t min_tps = 1024 * 1024 * 8;
>
> Also, do you have any stats showing the record rate and the delete
> rate?  Are you sure some other process (or maybe MythTV log files)
> wasn't what caused the disk usage to increase faster than free space?
> If so, those stats (and any info you may have on why the 120% ATSC max
> bitrate * number of cards didn't work for you) would be very useful.

Just `df -h' unfortunately

> If it is deleting too slowly, can you please try running mythbackend
> with a -v important,general,file (ideally logging to a different file
> system :) so we can see whether it's actually able to do 2 truncates per
> second or if there's an I/O wait issue or something slowing your truncates.
>
> Thanks for the question/spurring the discussion.  :)

I will try this tonight as well as watch some full episodes of the
recordings that occurred during the time snmp was emailing me..

Thanks,

Greg