[mythtv-users] Gig Network
ryan.goat at gmail.com
Sat Mar 10 13:47:26 UTC 2007
On 3/10/07, Blammo <blammo.doh at gmail.com> wrote:
> On 3/9/07, Henrik Beckman <henrik.list at gmail.com> wrote:
> > Multiple streams probably is harder on the drives than on the network,
> > anyone have som experience on how many streams SDTV and/or HDTV is
> >doable to a single spindel, without to much fragmentation (how large
> "blocks" are
> > written by myth?)
> There seem to be people who have "miracle drives" who claim record 4
> streams of HD, commercial flag, transcode, and watch 2 HD streams at
> the same time, all off one single spindle, one single drive, one
> single computer, integrated FBE/SBE.
> I am not one of those people. It would have been so much cheaper if I
> I discovered early on in my testing that a single spindle, even with
> sep front/back ends, was only good for about 1 stream of intensive
> usage at a time. What I mean by that is all operations, on a single
> stream. IE, record 1, playback 1, commercial flag 1, on a single
> Increasing any of those things to 2 or more, IE 2 tuners, 2 commerical
> flaggers, and you start seeing small problems with a single drive. You
> end up with "write timeouts" or "chunk/chop" in recordings, or sloppy
> playback, or etc.. not all the time, not every program, but it starts
> creeping in. You might be able to record 3 tuners, but as soon as
> commercial flagging starts in, you start seeing complains of "write
> timeouts" and your recordings start going to hell.
> The other thing that will tap the single drive (and tap 100Mbit
> ethernet) is Fast Forward and Rewind. You can flatline 100Mbit
> ethernet easily with anything over about 10x. With GigE you can run it
> well over 200Mbit, which is 20MB (roughly) which is about half of the
> sustained read rates (without concurrent seeks) of most current
> drives.. (which average 40MB to 50MB of real throughput a second)
> Commercial flagging, especially during the "logo detection" phase can
> slam the drive(s) with the same amount of demand.
> My current setup, of 4 tuners, 3 frontends, all HD, realtime
> commercial flagging, 2-3 transcoding sessions a day...... is
> impossible on a single spindle with any high percentage of success.
> But again, that's just me... maybe someday I'll find the "magic"
> drive. Till then it's just me and my raid array.. (oh how I love
My setup isn't quite as demanding as yours (4 HD tuners, 1 SD tuner, 1
networked frontend) but I have not seen any bottleneck issues with drive
performance. Even when recording several HD shows and watching another.
Have you tried increasing the PCI latency setting in your motherboard setup
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