[mythtv-users] Slow network causes myth to hang?

David Brodbeck gull at gull.us
Sun Feb 11 02:07:58 UTC 2007


David Campbell wrote:
> John Drescher wrote:
>   
>> I have the same problem with a 100Mbit wired Ethernet connection and 2
>> dual processor rigs. If I am moving shows from the master backend box
>> to the local machine (via nfs) the connection to database does not get
>> enough bandwidth and times out. It does this for any of the myth
>> utilities or the frontend. In the frontend this shows up as very slow
>> menus. In the utilities(transcode, mythcommflag, mytharchive ...) they
>> usually quit with an error.
>>     
>
> Wow - saturating a 100Mb link with mysql seems a little excessive to me. 
> Surely myth only needs to transfer the metadata?  I look after 
> production mysql databases that do 100 queries a second over 100Mb ethernet.
>   

I suspect it's not that the database uses all that bandwidth, it's that
with NFS saturating the network mysql can't get a packet in edgewise.

Another possibility is high processor usage.  Some cheap ethernet cards
demand a fair bit of it.  I have a 2.0 GHz Celeron system with a Realtek
8139 card in it, on a full-duplex 100baseT network, and using most of
the available bandwidth will cause 20% of the CPU to be consumed in
"system" processes. If I'm using a web browser or SMB file browser to do
the copy, the software and ethernet driver together can easily consume
over half the CPU.


More information about the mythtv-users mailing list