[mythtvnz] NFS performance not good enough?

[Worik Stanton]

I have a problem with my recordings not finishing.  On examining the
logs I see that it is due to disk performance.  I am writing to a disk
over NFS.  It should be able to take it, I thought, and these problems
have only started recently.

(See below for my logs and why I thing this is the problem)

So I have 2 questions for this list:

(1) Should I expect NFS to manage?  Searching the internet does not turn
up many other people having problems.  I have got file caching turned on
(using the 'fsc' option and cachefilesd.  (I'm turning that off now to
see if it helps)

(2) I have a local 32G ssd drive that is hardly used.  Can I get Myth to
record to it and move the recordings later as a scheduled job to the NFS
system?


For example I recorded Back Benches and at 16:17 the recording just stops.

The recording started at 22:29

The log said (mythbackend.log):

Jun  4 22:29:00 gently mythbackend[1425]: I Scheduler scheduler.cpp:2514
(HandleRecordingStatusChange) Tuning recording: "Back Benches": channel
1010
on cardid 5, sourceid 1
Jun  4 22:29:01 gently mythbackend[1425]: I CoreContext
scheduler.cpp:637 (UpdateRecStatus) Updating status for "Back Benches"
on cardid 5 (Tuning =>
Recording)
Jun  4 22:29:01 gently mythbackend[1425]: I TVRecEvent tv_rec.cpp:3989
(TuningNewRecorder) TVRec(5): rec->GetPathname():
'/media/Recordings/1010_20140604222900.mpg'

I assume it is writing to 1010_20140604222900

I get a few messages like:

Jun  4 22:42:50 gently mythbackend[1425]: W TFWWrite
ThreadedFileWriter.cpp:499 (DiskLoop)
TFW(/media/Recordings/1010_20140604222900.mpg:62): write(58280) cnt 90
total 5226776 -- took a long time, 14230 ms

Then the last mention of the file is:

Jun  4 22:51:33 gently mythbackend[1425]: E DVBRead
ThreadedFileWriter.cpp:216 (Write)
TFW(/media/Recordings/1010_20140604222900.mpg:62): Maximum buffer size
exceeded.#012#011#011#011file will be truncated, no further writing will
be done.#012#011#011#011This generally indicates your disk performance
#012#011#011#011is insufficient to deal with the number of on-going
#012#011#011#011recordings, or you have a disk failure.
Jun  4 22:51:40 gently mythbackend[1425]: W TFWWrite
ThreadedFileWriter.cpp:499 (DiskLoop)
TFW(/media/Recordings/1010_20140604222900.mpg:62): write(58092) cnt 2308
total 134209816 -- took a long time, 16819 ms


Worik

-- 
The only true evil is turning people into things....
                                         Granny Weatherwax
       worik.stanton at gmail.com 021-1680650, (03) 4821804
                          Aotearoa (New Zealand)

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