Crazy high buffer memory usage??




So I recently noticed that Plex uses all the buffer memory it possibly can.
Any reason why? Does this affect the general performance on my NAS?
In this graph you can see memory usage with all services of, and then I start only the Plex service.
Is this normal? I mean it shouldn’t be doing anything, no one is watching anything or adding new media?
Also if I then turn off the Plex service, the buffer memory don’t go down to normal usage…
I’ve read that usually buffer memory should be lower than cached, but that’s not what happends here.

I’m running a QNAP TS-469 Pro with 3 Gb memory, QTS


Be careful. Do not confuse normal Linux memory utilization with 'High' memory utilization.

Linux normally buffers (Buffer Cache) as much disk information (files and directories) as will fit in memory. Actual "Free" (completely unused) memory will be low.

The important point here is the used memory which appears to be less than 1GB on your system


Yes that's fine, but why does it only buffer that much memory when Plex service has been launched, no other service buffer this much memory??? And buffer memory still isn't Free memory. So I don't see why Plex should buffer that much memory when not even being used? I just want to know if this is a normal behaviour from Plex server or not?


The reason PMS causes the buffer memory to climb is because all the metadata directory bundles and files (each poster is a file) gets read once. It will sit in Buffer Cache as long as it can. When ANY application needs memory, Buffer Cache is the first reclaimed (it's read-only memory utilization and therefore instantly available)

Yes, this is normal memory utilization and of no consequence.


Thank you for explaining! :) Have a nice day!