[mythtv-users] Samba 3 better than NFS 3 for recording over Ethernet

Brandon Stoll mrmagoo at mrmagoo.org
Thu Dec 29 01:15:17 EST 2005

On 12/28/05, Yeechang Lee <ylee at pobox.com> wrote:
> Buechler, Mark R <Mark_R_Buechler at bausch.com> says:
> > My recordings directory is a raid5 set which isn't the fastest in the world
> [...]
> > Another thing I'm considering is HD. If I attempt to vew HD content from my
> > DVB card while streaming it to the raid5 array it can't really handle it too
> > well - whereas with a separate live tv buffer it wasn't a problem.
> I'm going to blatantly hijack this thread to record for posterity
> that, at least with my setup (streaming HDTV recordings to a software
> RAID 5+LVM2 array over Gigabit Ethernet with Fedora Core and the
> ATrpms version of MythTV 18.1), Samba 3 is rock solid while NFS 3 is
> pretty guaranteed to generate near-endless IOBOUND error messages in
> mythbackend.log. More detail when I have the time and inclination to
> write up my experiences, but I hope this helps others in my situation
> in the meanwhile; a month of IOBOUND error messages despite endless
> tuning attempts.
> --
> Yeechang Lee <ylee at pobox.com> | +1 650 776 7763 | San Francisco CA US

Since you brought it up...

    Is gigabit necessary?  I have 2 Myth systems connected via 100mbit
using CIFS/samba with relatively default settings - I searched google
I really couldn't find any options that would help aside from the
default socket options.  One machine is the BE/FE with PVR350+Air2PC
and the other a database/FE/RAID5 file server.  I don't have any major
problems with the SD recordings, although I have seen skips maybe once
per 3-4 hours of recorded content.  HD recordings regularly have tons
of IOBOUND that make shows unwatchable.  It seems like the 1080i
channels do this more than 720, although I thought 720p and 1080i were
effectively the same bandwidth.
   I tried NFS, but I could never get it to work right and had VERY
bad lag problems that would cause the kernel to become more or less
unresponsive until I would force an unmount of the share.
   I didn't think that recording only 1HD/1SD stream could have
problems with 100mbit full duplex, but I'm at a loss as to what other
settings I should be looking at.  I'm hoping there are some buffer
settings with the new HD recorder code in SVN [that patch made some
shows watchable] but I'm not sure where to look for that, or if that
would even help me.

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