[mythtv-users] NFS and remote backend
pat at flying-gecko.net
Mon Jan 14 16:51:34 UTC 2008
On Mon, Jan 14, 2008 at 08:38:19AM -0800, Jason wrote:
> I was seeing a lot of stuttering with NFS being the source for video files,
> with the worst showing in shows being recorded. I switched to streaming
> direct from the backend and most of the stuttering went away.
> The only place I see stuttering is when I'm watching something already being
> recorded, or watching live TV. The stuttering only seems to occur when I'm
> watching close to the end of the recording (i.e. almost at real time). If I
> pause for about 10 seconds, the stuttering goes away. On the frontend, I
> see lots of the "prebuffering pause" messages during this stuttering, which
> is expected. I do see prebuffer issues at other times, but I don't recall
> noting an actual stutter in the playback. If there is, it's quite small and
> mostly unnoticeable.
> I've got gigabit network between the backend and frontend. My HD recordings
> come from a HDHomeRun. I have not implemented jumbo packets on the gigabit
> network. For network performance purposes, I'm looking to implement
> ethernet bonding for the backend (I've got two gigabit ports on the
> motherboard) and possibly vlans to segregate gigabit with jumbo packets from
> the rest of the network. (I don't think those changes would really help
> anything other than my own sense of "it's running best it can".)
> I installed a DCH3200 set top box from comcast over the weekend, connected
> via firewire, and noticed the same stuttering issue with that source.
> Again, pausing helped the problem.
> One item of note: I can record two HD streams from the HDHR and watch a
> previously recorded HD program without any stuttering, so it appears that
> all the hardware can "keep up" with the requirements. Something just breaks
> down when I'm watching something being recorded that is close to the end of
> the file.
> Given that I'm seeing the stuttering without NFS, I'm not sure it's the
> source of the problems. Nor would I imagine moving to Samba/CIFS would
> help. Maybe it's some sort of file system problem on the backend (locking,
> etc?). I'm using ext3 on the media partition.
> Aside from doing the work to figure out that streaming from the backend
> helped, I haven't done much to suss out the reason for this. I accepted the
> situation it was in and the relevant requirement to hit pause at the start
> of live tv.
Could this be a case of MySql not keeping up? Database writes slowing
down the availability of the inprogress recording?
Patrick Ouellette pat at flying-gecko.net
kb8pym at arrl.net Amateur Radio: KB8PYM
Living life to a Jimmy Buffett soundtrack
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