[mythtv-users] Performance Issues with Network Drive

Michael T. Dean mtdean at thirdcontact.com
Thu Sep 17 03:45:27 UTC 2009


On 09/16/2009 07:47 PM, C.T. Paterson wrote:
> I have a Mythbuntu 8.10 BE/FE box sitting in my entertainment unit.
> The OS runs off of a USB stick (high temp was killing internal
> drives), and all the media is actually on a pair of SATA drives in a
> DNS-323 NAS.
>
> The myth box and the NAS share a GigE connection.  The drives are
> mounted on the myth box using cifs.  To illustrate completely,
> watching live TV consists of the tuner card in the myth writing data
> to the mounted drive (the NAS), and then reading the data back from
> that drive, and putting it out to the TV.
>
> - I get the occasional hiccup on playing back an mpeg4 or avi file (my
> compressed videos)
>   

Unfortunately we don't (yet) have a wiki page on optimizing CIFS/Samba 
performance for Myth, but we'd love for you to start one.  :)

Also, the MythTV recordings workaround "Always stream recordings from 
the backend" ( 
http://www.mythtv.org/wiki/Troubleshooting:Prebuffering_pause#Network_I.2FO_Related_Issues 
) won't help with MythVideo videos (at least in 0.21-fixes).

However, I know that there have been many threads on optimizing CIFS 
performance, so my recommendation would be to search the archives ( 
http://www.gossamer-threads.com/lists/mythtv/ ), and if you'd be so kind 
as to create a wiki page with your findings, it will make this much 
easier for others in the future.

Yeechang Lee was (is?) using CIFS-based storage and had done a lot of 
work on testing/optimizing things.  I'm primarily mentioning him in case 
he wants to jump in with some info.

> - I can almost never change the channel without encountering a timeout
> that puts me back at the main menu.  Sometimes it will even crap out
> when I'm just watching live TV.
>   

This is likely due to the same issue we've been discussing in the 
thread, "How do I get coverart/etc in watch recordings?" ( 
http://www.gossamer-threads.com/lists/mythtv/users/397750#397750 ).  
Whereas in NFS you specify actimeo=0, CIFS/Samba use a different 
approach.  At one point it was the ttl (time-to-live) option, but I 
think the CIFS driver uses a completely different approach to 
configuring it.

http://www.mythtv.org/wiki/Optimizing_Performance#Network_File_Systems

Anyway, I hope that mentioning those actimeo and ttl will get you 
pointed in the right direction to find the equivalent option for CIFS.  
(And, if you do, your adding it to the wiki page linked just above would 
be greatly appreciated.)

Thanks,
Mike



More information about the mythtv-users mailing list