[mythtvnz] Recording dropouts and disk performance...

[Chris Bannister]

On Sat, Feb 16, 2013 at 03:32:18PM +1300, Rob Connolly wrote:
>  
> Hi All,
> 
> Over the past couple of weeks I've had a few recordings drop out after
> several minutes. Today I finally got around to looking in the log files
> for one of the affected recordings:
> 
> 2013-02-14 21:38:59.782815 E [1609/24862] DVBRead ThreadedFileWriter.cpp:217 (Write) - TFW(/mnt/recordings/1001_20130214083000.mpg:110): Maximum buffer size exceeded.
>                         file will be truncated, no further writing will be done.
>                         This generally indicates your disk performance 
>                         is insufficient to deal with the number of on-going 
>                         recordings, or you have a disk failure.
> 
> My disk setup is 2x2TB drives set up using software RAID 1 and LVM, with
> the system and database partitions being hosted on the same drives as
> the recordings. This setup has worked fine until recently - I did have
> one drive die a while back, but I returned it under warranty.

Have you had a look at hdparm?
i.e hparm -tT /dev/sdx
(where x is the letter of your device)

Is dma turned on for all drives?

I have no experience with RAID, so don't know how useful hdparm is in a
RAID setup.

-- 
"If you're not careful, the newspapers will have you hating the people
who are being oppressed, and loving the people who are doing the 
oppressing." --- Malcolm X