[mythtv-users] Problems with multiple pvr cards

[Brian Walter]

Michael T. Dean wrote:
> On 05/09/2007 11:43 AM, Brian Walter wrote:
>   
>> Tom Lichti wrote:
>>   
>>     
>>> Brian Walter wrote:
>>>       
>>>> Well, I think I have isolated it to something in the disk subsystem.  I 
>>>> upped the default write buffer in libmythtv, and, lo and behold, the 
>>>> error now only occurs once every 30 minutes...
>>>>         
>>> Is your backend also running mysql? If so, and the errors are occurring 
>>> on the half hour, it's likely the scheduling queries that are causing 
>>> the error. I have 2 PVR-250's, 1 PVR-150, and an HDHR with one HD and 
>>> one QAM/SD tuner setup, and I can record from all 5 at once with only 
>>> very occasionally getting a buffer problem (which does not take down the 
>>> whole box, btw), but I have the database on another machine, and I am 
>>> running a RAID5 disk, so it can be done.
>>>       
>> Yeah, I'm beginning to think RAID might solve a lot of problems.  
>> There's nothing else running on the backend except the backend.  Mysql 
>> is on another machine, as is all the commflag jobs.
>>     
>
> As a point of reference, I'm running MythTV 4-PVR-250 combined 
> frontend/backend with the MySQL server (and a bunch more) on a machine 
> without RAID and can successfully record from all 4 PVR-250's while 
> doing 1 commflag job and playing back a previously-recorded show.
>
> Although I'm not now, I used to run this setup with LVM for the 
> recording partition.  IMHO, simple is the best approach.  MD (RAID 
> and/or LVM) adds complexity and isn't really necessary for a DVR (at 
> least with my interpretation of the value of recorded TV).
>
> I'd say check your UDMA support, make sure you're using the proper 
> chipset driver for your motherboard, and don't put the recordings 
> directory on the same disk (and, ideally, not on the same bus) as the 
> root partition.
>
> Mike
> _______________________________________________
>   
Mike,

Thanks.  Valid points that got lost in the forest of trying to solve this :)

I'll check all those things out.

Brian