Docker system requirements guidelines

[janoonk]

Hi,

I am running NextPVR with Docker running on my Synology NAS DS720+ with an INTEL Celeron J4125 and 8GB memory.
I use a quad tuner HDHomeRun Expand.

What is a good memory and cpu limit to use? Any tips/guidelines?

I can choose between Low, Med and High for CPU limit.
And I can set an amount of memory limit.

Thanks.

[sub]

To be honest, it's hard to know (varies between platforms, and different types of devices, number of channels, days of listings etc). I'd try it with low initially, and see how it performs, and bump it up if necessary.

If you're intending to view video in the web app, which requires transcoding, you'd probably need to let it have high CPU limit. If you're using intending to use a client that can do native video playback, you wont need to do this.

[pkscout]

I've got NextPVR running on Docker on a similar Synology NAS (920+). I don't use any of the transcoding for the web client (although it does work from the couple of tests I did).  Here's what my usage looks like with two recordings going from an HDHR Prime.  The memory seems to spike a fair amount during recording, but I've not seen it much higher than what is shown here. The CPU almost never does anything.

[mvallevand]

I would be concerned setting RAM too low, since it would likely still use swap if needed which could be noticeable.

Martin

[janoonk]

I've got NextPVR running on Docker on a similar Synology NAS (920+). I don't use any of the transcoding for the web client (although it does work from the couple of tests I did).  Here's what my usage looks like with two recordings going from an HDHR Prime.  The memory seems to spike a fair amount during recording, but I've not seen it much higher than what is shown here. The CPU almost never does anything.

Yeah same here... during 4 parallel recordings (using a HDHomeRun Expand quad tuner) the CPU does nearly nothing... max I have seen is 1-2% (I have set it to Low CPU priority).
After 30-45 minutes of recording the memory went from 0.4GB to 2GB, which was the max. memory limit I set. But I didn't notice a performance degradation when it hit that limit.
So I keep these settings, works for me.

[tsanga]

I have Plex running natively on my Synology and NextPVR in a Docker container.

Recording the same program from the same HDHomerun, I get frame drops/corruption in my NextPVR stream. Yet the Plex recording is smooth. I’ve debugged with the hdhomerun_config CLI and found no network or transport errors.

My only guess is there’s something interrupting the Docker, maybe related to CPU prioritization. Has anyone discovered that setting CPU prioritization matters?

[sub]

I have Plex running natively on my Synology and NextPVR in a Docker container.

Recording the same program from the same HDHomerun, I get frame drops/corruption in my NextPVR stream. Yet the Plex recording is smooth. I’ve debugged with the hdhomerun_config CLI and found no network or transport errors.

My only guess is there’s something interrupting the Docker, maybe related to CPU prioritization. Has anyone discovered that setting CPU prioritization matters?

For the most HDHomeRun devices NextPVR will use a TCP connection, so there shouldn't be any opportunity for dropped packets etc.

How are you watching the stream? If you're watching in the web app, it's probably a case of the CPU not keeping up, and you'd find if you were watch in a client that plays native streams, like Kodi etc, then the CPU will be low and no issues.

[tsanga]

For the most HDHomeRun devices NextPVR will use a TCP connection, so there shouldn't be any opportunity for dropped packets etc.

How are you watching the stream? If you're watching in the web app, it's probably a case of the CPU not keeping up, and you'd find if you were watch in a client that plays native streams, like Kodi etc, then the CPU will be low and no issues.

I’m watching the recordings, often with a time delay, using Plex in direct play mode (no transcoding). So it’s not like I’m taxing the CPU by playing back in NextPVR web client. Also, the frame drops are written into the .ts file, and not occurring during playback. If I rewind, they’re always at the same moments in the broadcast.

That’s why I’m suspecting something to do with Docker, or I’m not setting it up right.

[mvallevand]

That sounds more like signal than TCP errors. OTA or cable card?

Martin

[tsanga]

That sounds more like signal than TCP errors.  OTA or cable card?

Martin

OTA

Just tested another recording. I’m using a dual tuner HDHomerun.

One tuner on Plex, the other on NextPVR+Docker, same channel.

The one on Plex recorded and played fine. The NextPVR recording had frame drops exactly as if I was having reception issues. I tried increasing CPU priority on Docker but still had issues.

Can I make NextPVR switch between the two available HDHomerun tuners as a test? Do I need to delete one from settings?