Memory on DSM7 with PMS (many versions, stretching back over a year)

Server Version#: 10.32.7.7621-7000

For a while now (at least a year) PSM will occasionally start consuming all the ram on my Synology (DSM7 on 1019+) with 16GB of ram until it finally causes everything to stop responding and if I’m lucky, DSM will kill PSM. If I’m unlucky, I get to spend 10-20 minutes slowly logging into the web interface to manually kill PSM.

Curious what else could be causing this. I don’t see this behavior on my DS1819+. Pretty sure settings are as identical, but i could be missing something…

Do you have the DLNA server enabled? There’s a known memory leak that isn’t likely to be fixed.

nope. sorry, thought I had that in my post but I guess not. lol. Not enabled on either 1019+ or 1819+

The J3455 CPU supports a MAXIMUM of 8GB of RAM.

https://ark.intel.com/content/www/us/en/ark/products/95594/intel-celeron-processor-j3455-2m-cache-up-to-2-3-ghz.html

Putting more than 8GB into the machine causes a false read by Linux (it doesn’t know what the CPU’s maximum is)

This is the kind of problem which occurs – You get memory corruption and then it ultimately blows up because it slowly uses different parts of memory (which it thinks is all safe) until it writes somewhere it shouldn’t… UT OH!)

Reduce the installed memory to 8GB.

Ignore the “Unofficial” tricks found on the internet.

It’s run “fine” with 16GB for years. Plex is the only thing that seems to have any issues. Kingston even says 16GB is supported: Memory for a Synology - DiskStation DS1019+ - Kingston Technology

I understand this isn’t what Intel says, but previous years of experience and the web of people saying 16GB works seems to say otherwise. =/

Would the plex logs indicate anything when this happens to show what’s going on?

How much 4K video transcoding and HDR tone mapping do you do now?

The issue with 16 GB of RAM in an 8GB machine – and the kernel trying to use it comes when

  1. The i915 / i965 QSV perform the transcode – They will allocate anything they want from all of defined memory

  2. OpenCL (tone mapping) , which runs in the GPU of the CPU will also allocate whatever they want.

I know people claim it SEEMS to run fine but I’ve never had ANY issues with anyone running 8GB max in the machines.

Kingston sells memory – PERIOD. They advertise a kit with is compatible (from the electrical perspective – not a functional perspective)

Older CPUs (Atom C2538) actually will safely address 16 GB but the newer J-series will not. That’s a change by Intel.

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No HDR tone mapping at all. And 4k transcoding, barely any?

Understood this is all seems, and that kingston sells memory. I’m kind of saying “let’s put aside this as the assumed cause, and actually find evidence it is”.

Based on nothing specific, it does seem to be triggered randomly. It could be credits or into detection, or I think I saw a thread about Cloud Sync possibly causing an issue? Cloud sync only syncs the database backup.

So, watching the logs… I do see

"Library section 1 (TV Shows) will be updated because of a change in “/volume1/Data/TV/Icon”

This is recurring every minute or so… so scan completes, re-triggers. Wonder if the re-scans are just backing up.

I am using resilio to sync my content between Synologies… clearly that might be causing some issue. My other synology does not seem to be going into this loop…

Is it possible to have Plex ignore the change to the icon as a trigger for a re-scan?

Update:
not sure it was it, but found setting in Resilio “sync_extended_attributes” and disabled that. Disabled that, and that SEEMS to have calmed down the re-scanning. Before it was constant… resilio didn’t have anything in the logs indicating it was doing anything, but who knows… will keep an eye on it.

This is not the PMS server version. Do you mean 1.32.7.7621-871adbd44

You’re kinda grabbing at straws by saying “it could be this or that” which isn’t any more fair than you refuting my observations about what these machines do when incorrectly fitted with memory.

How about we get more scientific ?

  1. Confirm DEBUG logging is enabled, VERBOSE logging is disabled (Settings - General - Show Advanced ) SAVE & Restart PMS if you make changes.

  2. When it next misbehaves -
    – Stop PMS
    – Open FileStation
    – Navigate to PlexMediaServer/AppData/Plex Media Server
    – Right-click LogsCompress to Logs.zip
    – When it completes , Download the ZIP file
    – Attach the ZIP file here

  3. At that point, if you’ve caught it early enough, we’ll see what it’s doing.

I have my doubts about Credit and Intro Detection for several reasons.

First and foremost, We’d be swamped with other posts of the same thing
Second, I’d easily be able to reproduce it on my 1 GB DS418j (DSM 7.2.1 running 1.32.7).

My development server runs for weeks without issues.

It is networked to my main file server so it sees each piece of new media I add there and adds it to the DS418’s library as well.

That all said, let’s do this and see what we find.

Are you running torrents which write directly to your media libraries (which PMS is watching) ?

No, no torrents directly into any PMS folders… but Resilio does use BT as it’s underpinnings. Still seeing everything nice and quiet since adjusting that setting.

And yes, I agree. Will turn on debug and get some logs if I see this happen again. atm I’m going to see if it reoccurs since the Resilio change since it would make sense if the scanning was “stacking up” it could eventually cause some memory exhaustion.

The logs definitely look significantly quieter now.

That said, the logs only seem to go back 1-2 days (when downloading the logs via the plex web gui). Is that an adjustable setting? ideally it would be nice to keep a week or more so if this reoccurs I could actually see the start of the issue.

Another thing to be careful of –

PMS is now sensitive to permission changes.

If you have a script / tool which blindly sets all the permissions on media
then PMS will be constantly retriggered every time it scans.

I have a FAQ / How-To to set permission changes automatically without disturbing those already set.

Let me know if you need it.

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Thanks Chuck. It may be that was the issue (the permissions on the folder icon changing). But unclear.

So now my movies folder is doing same… saying it’s rescanning because the icon changed. Is there any way to tell Plex to not care about the folder icon?

"Library section 5 (Movies) will be updated because of a change in "/volume1/Data/Movies/Icon " "

Managed to, I think, fix, by deleting the “Icon” file from DSM. Guess we’ll see if it stays gone…

Because I am using Resilio, I also went in and added “Icon” and made sure “Thumbs.db” were in the list of IgnoredFiles. See here: https://help.resilio.com/hc/en-us/articles/205458165-Ignoring-files-in-Sync-Ignore-List-

Somehow these files existed (and were very old) and somehow were getting changed (or maybe failing to process) and causing Plex to loop endlessly scanning the directories. =/

Another update… seems like the scanner is occasionally rescanning an entire folder even though it’s been told to only do partial scans. Is this a known issue?

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