[mythtv-users] Mythbackend recording glitches

[Stephen Worthington]

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.