Mailing List Archive

MythTV and NFS
Folks -

Has anyone here attempted to record using MythTV on an NFS-mounted volume?
I plan to run MythTV on a 1Ghz Duron with a WinTV PVR250. I have a 100MB
home network, and I don't think it'll be a problem. Can anyone verify?



--
-------Patrick M Geahan----pmgeahan@thepatcave.org---ICQ:3784715------
Quote of the Week: "I probably won't start on the idea, and if I do it
will wind up being an unfinished project on my personal website featuring
pictures of my cat." rh2600 on /.
Re: MythTV and NFS [ In reply to ]
Patrick M Geahan wrote:

>Folks -
>
>Has anyone here attempted to record using MythTV on an NFS-mounted volume?
>I plan to run MythTV on a 1Ghz Duron with a WinTV PVR250. I have a 100MB
>home network, and I don't think it'll be a problem. Can anyone verify?
>
>
>
>
>
I use NFS (read more about my setup at
http://www.gossamer-threads.com/perl/mailarc/gforum.cgi?post=58030;search_string=nfs;guest=369558&t=search_engine#58030).
From a quick search of the archives, it seems that many people are
using it. There is a discussion of NFS performance at
http://www.gossamer-threads.com/perl/mailarc/gforum.cgi?post=56426;search_string=nfs;guest=369558&t=search_engine#56426.
Personally, I see no reason not to use NFS, other than it makes it
difficult to identify performance problems since it add another variable
to the mix.
Re: MythTV and NFS [ In reply to ]
I'm actually going to be trying this in a few days, but I'd recommend
at least using the async option on the nfs server. This will allow the
nfs client go about it's business while the server writes to disk. a
little dangerous if you don't have a ups, but I think this is
non-mission critical stuff we're dealing with here.


On Monday, April 21, 2003, at 09:01 AM, Patrick M Geahan wrote:

>
> Folks -
>
> Has anyone here attempted to record using MythTV on an NFS-mounted
> volume?
> I plan to run MythTV on a 1Ghz Duron with a WinTV PVR250. I have a
> 100MB
> home network, and I don't think it'll be a problem. Can anyone verify?
>
--
Tod Detre
Unix Support Specialist
Case Western Reserve University
unixsupport@po.cwru.edu
216-368-3060
Re: MythTV and NFS [ In reply to ]
> Has anyone here attempted to record using MythTV on an NFS-mounted volume?
> I plan to run MythTV on a 1Ghz Duron with a WinTV PVR250. I have a 100MB
> home network, and I don't think it'll be a problem. Can anyone verify?

MythTV has been working great over NFS for me. My main backend server only
has a 2GB hard drive and all video and mp3 storage is on my file server.
I also run several other frontends.

Myth has been modified in several places to make it more friendly to NFS
users. I'll describe my setup and describe how.

Normall have 4 computers involved:
mythtv - Master backend (also runs Frontend #1 and the MySQL server)
panther - Frontend #2 (occasionally runs slave backend)
pooh - Frontend #3 (wife's Linux box)
taz - Fileserver

/usr/vcr/mythtv/recordings is my video storage directory and it is shared
and mounted on all 4 servers in the same location.

When a program is recorded, an entry gets saved in the recorded table with
the hostname of where it was recorded. If a file was recorded on a slave
backend but the slave is down, you would not normally be able to watch any
programs recorded on that backend. Mythbackend was modified so that if
a slave is down but the recorded file can be accessed locally (ie, over
nfs or perhaps backend is the nfs server), then the master mythbackend will
stream the file itself while the slave is down.

The ringbuffer code has been modified to make mythfrontend more efficient
also. If the backend server tells the frontend to stream a file from
a backend server (by giving a myth:// url) the frontend checks to see if
the file is available locally. If the file can also be read directly
(ie over nfs), then the frontend reads directly rather than going through
the backend. This can cut down on sending file data twice over the network
just to play a file (ie from fileserver -> backend server -> frontend server).
This helps most in situations like mine where my files are stored on a
3rd server that isn't a backend or frontend.

You probably didn't want all that information, but I figured it might be
helpful to you or someone else to know how they could benefit from using
nfs in their myth environment. I run my slave backend only part of the time
but all recorded files are still available everywhere even when the
backend is down.

Chris

*****************************************************************************
** Chris Pinkham Linux v2.2.18, Sane v1.0.4, Cajun v3.0-8 **
** cpinkham@bc2va.org http://www.bc2va.org/chris/ **
*****************************************************************************
Re: MythTV and NFS [ In reply to ]
I've not recorded directly to an nfs volume but I frequently watch recorded
shows from nfs. Works just fine with 100Mb Ethernet.

Regards,
Doug
Re: MythTV and NFS [ In reply to ]
Tod Detre wrote:

> I'm actually going to be trying this in a few days, but I'd recommend
> at least using the async option on the nfs server. This will allow the
> nfs client go about it's business while the server writes to disk. a
> little dangerous if you don't have a ups, but I think this is
> non-mission critical stuff we're dealing with here.


According to the man page, the sync (and async) options are only valid
on ext2, ext3 and ufs. It doesn't cause an error when used, but it does
not appear to have an effect and does not show up as one of the options
in /proc/mounts. Here are the NFS options I am using,I get fairly good
performance from this setup (2 backends writing to a third file server):

rw,noatime,rsize=8192,wsize=8192,hard,intr,nfsvers=3



>
>
> On Monday, April 21, 2003, at 09:01 AM, Patrick M Geahan wrote:
>
>>
>> Folks -
>>
>> Has anyone here attempted to record using MythTV on an NFS-mounted
>> volume?
>> I plan to run MythTV on a 1Ghz Duron with a WinTV PVR250. I have a
>> 100MB
>> home network, and I don't think it'll be a problem. Can anyone verify?
>>
> --
> Tod Detre
> Unix Support Specialist
> Case Western Reserve University
> unixsupport@po.cwru.edu
> 216-368-3060
>
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