[mythtv-users] Mythbackend recording glitches

[Allen Edwards]

On Thu, Oct 18, 2018 at 8:07 PM Stephen Worthington <
stephen_agent at jsw.gen.nz> wrote:

> On Thu, 18 Oct 2018 17:03:45 -0700, you wrote:
>
>
> >Can anyone say that if I go to 4G or ram with the AMD 5400 that I will not
> >run into some other limitation? I feel I grossly underestimated the effort
> >and overestimated the benefit of upgrading to Mythbuntu 16.
> >
> >Perhaps I just need to figure out how to move everything from my 500G
> drive
> >to my new about to be delivered 1T drive.
> >
> >Allen
>
> Since my mother's system is OK with 4 Gibytes of RAM, the same should
> apply for you if you upgrade your RAM.  But we have not actually
> proved what is causing the recording glitches yet, so there is no way
> to be sure.
>
> My recommendation for anyone starting out setting up a new MythTV box
> now would be to go for 8 Gibytes of RAM.  Sadly, the major Linux
> distros have gone down the same path as Windows (although not as
> badly) and now need much more RAM.  I tried running Ubuntu 16.04 on my
> original MythTV motherboard (Asus M2NPV-VM) a couple of years ago.  It
> only had 2 Gibytes of RAM, but had a builtin (ancient) Nvidia GPU, and
> I thought it would be fine for just running Linux and testing new
> MythTV things.  But it was not a good experience at all.  It turned
> out that both the system and MythTV now need much more RAM.  So I
> bought a second hand Nvidia 220 card and tried using my slightly more
> recent Asus P5K-E motherboard, which used to be my old Windows Vista
> system.  It has a Core2 Duo CPU and 4 Gibytes of RAM and works pretty
> well.  I used it for my main MythTV system for a week when I had a bad
> problem on my real MythTV box, and it handled that, although I had to
> be careful not to schedule too many recordings at once.
>
> My current main MythTV system is an Asus M5A97 EVO motherboard and AMD
> FX-4100 quad core 3.6 GHz processor.  It has 8 Gibytes of G.Skill
> F3-1866C9D-8GAB RAM, which is a good match to the CPU and motherboard.
> But even with 8 Gibytes of RAM, it does use swap space, but only for
> things that are not used, rather than having to swap things back into
> RAM all the time.  It is a big system - a super fast NVMe SSD for
> Ubuntu 18.04 and my swap space, 7 recording drives, 3 video and other
> data drives, 8 DVB-T2 and 8 DVB-S2 tuners.  It only actually uses 5 of
> the DVB-T2 tuners (we only have transmissions on 5 frequencies here in
> New Zealand), and 5 of the DVB-S2 tuners for my pay satellite service.
> One other DVB-T2 and one other DVB-S2 tuner are used once a day for
> gathering EPG data.  It does regularly have 14+ recordings in progress
> at once.  Mythcommflag is no longer used, as it does not provide
> useful marking of the ad breaks on any of our channels here in NZ. But
> I used to use it all the time and it works in real time on 4
> recordings at once and is able to catch up rapidly when more than 4
> recordings happen at once.  I have over 30,000 recordings, so
> mythfrontend needs lots of RAM to be able to create a full list of
> them all.  That seems to be the thing that causes my swapping more
> than anything else.  So when I next upgrade my MythTV box, I plan on
> at least 16 Gibytes of RAM.
>
> If you want to move you old system across on to your new hard disk,
> then you can use gparted for that.  I am not sure if gparted was
> available in your old system, or just how capable it was, but if you
> boot to your Mythbuntu 16 partition and run it from there with both
> the old and new hard drives attached to the box, you can copy, move
> and resize partitions between all the drives.
>
>
Thank you Greg, Stephen, and everyone else who has helped me.

This has been an education and your help is very much appreciated.  Where I
am right now is that we just watched a show that previous to my attempt at
fixing the Mythbuntu 8 setup was unwatchable. It would crash every 10
minutes.  We watched it without glitches or tearing on the old Mythbuntu 8
system.

There were several reasons I did the upgrade to Mythbuntu 16.  One is that
the Mythbuntu 8 system was crashing and I thought somehow that whatever
caused the one drive to prevent booting had damaged the main drive as I was
seeing problems with both.  At first I had suspected the disk controller
and that may yet be the case. Hopefully that is not the case as I will need
three drives to do the cloning.  The other was that I wanted to see some
improvement in video quality, commercial detection, and any other
performance improvements ten years would have produced.  But to tell the
truth, I saw none of that even though I put in a higher power video card
and did get everything working, except for the occasional glitching.

But the effort was not completely wasted because it was only though
familiarizing myself again with the system that I was able to figure out
how to stabilize the old system.  In hindsight, I should have troubleshoot
the old system but I had all the reasons listed above to upgrade.  At first
I thought I would need all new hardware but just thought I would give the
old hardware a try and we all know that story. Just over that next hill.

If I do find the need to continue with the upgrade at least we have learned
some things. We know for sure that the glitching is not caused by coax,
antenna, connectors, tuners, ethernet,etc. It may be swap or it might be
some cron job I don't know about.  If I were to continue on the path of
getting -16 working I would purchase THIS
<https://www.amazon.com/gp/product/B002N52ZO4/ref=ox_sc_act_title_1?smid=A26PVB3960EU85&psc=1>
memory. It is slower than the memory I have now but there is more of it and
if I can add it to what I have, I would have 6GB, otherwise 4GB. But at
this point I see no benefit for doing so. Perhaps this is because I am
recording 720P video and watching it on a 720P display so I am not asking
as much from the system. I don't know but it works just fine and I am tired
of chasing one problem after another only to still not have a system as
good as what I had ten years ago.  If that doesn't work, I would try again
to specify all new hardware and start with a modern system.  But even that
is not painless as I have been unable to find a case that works in my setup.

At this point my plan is to clone with Clonezilla and if that doesn't work,
I will try gparted, which is not on my old system so I would need three
drives hooked up anyway.

Cheers,

Allen
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