Mailing List Archive

Question to all those NFS users out there...
It has become apparent to me that NFS is going to be an option that I'll
need to pursue, so that multiple front-end machines can access MythVideo,
MythGallery, and MythMusic data. I'm curious what kind of bandwidth
issues people are seeing?

I'm envisioning a backend machine with two tuner cards, and then two
frontend systems (at the TVs in the house) and then of course no reason
not to install the frontend on one of my workstations as well. I'm just
guessing here, as I don't have snmp capable switches at home, but it seems
to me that the poor NFS system's 100Mbps could potentially be a problem.
Are people running multiple NICs in their NFS systems to reduce this as a
potential bottleneck? Certainly 100Mbps for two streams being saved by
the backend, and 100Mbps for potentially three mythfrontend video streams
should negate any possible bandwidth issues.

~cj
#mythtv.conaz
RE: Question to all those NFS users out there... [ In reply to ]
> -----Original Message-----
> From: mythtv-users-bounces@snowman.net
> [mailto:mythtv-users-bounces@snowman.net]On Behalf Of Christopher Maahs
> Sent: Friday, June 13, 2003 10:24 AM
> To: Discussion about mythtv
> Subject: [mythtv-users] Question to all those NFS users out there...
>
>
> Certainly 100Mbps for two streams being saved by
> the backend, and 100Mbps for potentially three mythfrontend video streams
> should negate any possible bandwidth issues.
>

Why do you need network bandwidth for the two recordings being saved by the
backend? Barring other factors in your particular setup, you'll get the
best performance (and save bandwidth) by putting your video storage
partition/disk directly in your backend box.

-JAC
RE: Question to all those NFS users out there... [ In reply to ]
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

You're not sending uncompressed video across the network, so 100Mbps
is plenty. Why would you think you need two NIC cards?

-----BEGIN PGP SIGNATURE-----
Version: PGPfreeware 7.0.3 for non-commercial use <http://www.pgp.com>

iQA/AwUBPunkjfc1NpCTlP0JEQIvowCffOM1Az7DZo/09QgN8eLgbXZ4/CkAoLI/
uXsj1kfjr/yzhNtl3IN8W5Jv
=6gma
-----END PGP SIGNATURE-----
RE: Question to all those NFS users out there... [ In reply to ]
On Fri, 13 Jun 2003, Joseph A. Caputo wrote:

> Why do you need network bandwidth for the two recordings being saved by the
> backend? Barring other factors in your particular setup, you'll get the
> best performance (and save bandwidth) by putting your video storage
> partition/disk directly in your backend box.
>
Excellent point, I guess either way we are still talking about the same
amount of disk access.

~cj
RE: Question to all those NFS users out there... [ In reply to ]
On Fri, 13 Jun 2003, Robert Kulagowski wrote:

> You're not sending uncompressed video across the network, so 100Mbps
> is plenty. Why would you think you need two NIC cards?

I wasn't sure if 5 streams would require more than that. Of course it
would be a very unlikely real-world situation to have 2 recordings and 3 viewings
going on at one time.

Based on the other reply, keeping the NFS storage on the backend, I'd be
down to only the 3 streams, so that sounds good to me.

~cj
#mythtv.conaz
Re: Question to all those NFS users out there... [ In reply to ]
> It has become apparent to me that NFS is going to be an option that I'll
> need to pursue, so that multiple front-end machines can access MythVideo,
> MythGallery, and MythMusic data. I'm curious what kind of bandwidth
> issues people are seeing?

That's easy. None.

To calculate your minimum bandwidth needed, just look at your recording
bitrate. If you're recording at 3500kbit/sec, that's only 3.5 megabit
per second, so you could record or playback over 15-20 of these at the
same time on a 100Mbit switched network, and probably at least 10 if
you're using a hub.

If you're using a pvr-250 recording at the 8Mbit avg, 16Mbit max then
you do 5 or so at a time at least, maybe 10.

Chris