[mythtv-users] NFS and remote backend

Steven Adeff adeffs.mythtv at gmail.com
Fri Jan 11 15:40:16 UTC 2008


On Jan 11, 2008 10:25 AM, Brad DerManouelian <myth at dermanouelian.com> wrote:
> On Jan 11, 2008, at 7:10 AM, Steven Adeff wrote:
>
> > this isn't much help, but I noticed the same thing. NFS transfers are
> > painfully slow and actually eat up a lot of "overhead" whereas FTP
> > uses the full bandwidth and doesn't seem to eat up "overhead".
> >
> > I first noticed this when I switched my network to 1000bT. I used to
> > transfer files between my master backend and my frontend (where my
> > long term storage array is) via NFS but was noticing that when I did
> > my recordings at that time would become choppy, the transfer speed was
> > no faster than on my 100bT network and I couldn't watch an HD show on
> > the frontend while transfering, it would just be choppy.  Then I tried
> > FTP for the heck of it and it used the full network speed, did not
> > affect recordings and allowed my frontend to play an HD show (with th
> > obvious slowdown in the file transfer) without any problems.
> >
> > So there is definitely something wrong with the base setup of NFS
> > somewhere. I couldn't figure out what, but at least I'm not the only
> > that noticed this problem.
>
> Not wrong, just optimized for transferring lots of little files, not
> the other way around.
>
> > For now I've just been using FTP until someone can tell me why this is
> > happening.
>
> I followed the instructions here
> http://www.mythtv.org/wiki/index.php/Optimizing_Performance#NFS_servers
>
> set my options in /etc/fstab for my nfs mounts to:
> actimeo=0,intr,soft,rsize=16384,wsize=16384,nfsvers=3,tcp
> I also had to specify async mode on the server side.
>
> Now I don't have a problem recording a couple of HD streams while
> watching and commflagging any more.

interesting, I'll have to try this. I don't record over NFS, just
transfer files and stream to other frontends/laptops, but between the
backend and the frontend I use it to transfer recordings I want to
save, HD ones can be huge!

crosses fingers as he ssh's into his home network from work....

thanks!
-- 
Steve
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