RAM full at 70% but I can only see 10% using top

Blabla · Mar 25th 2020

Hi everyone,

I don't get why my RAM is nearl full even ifall my containers combined use around 1,5GB.

This is the result of top:

Code

top - 12:36:23 up 1 day, 20:05,  1 user,  load average: 0.00, 0.00, 0.00
Tasks: 225 total,   1 running, 223 sleeping,   0 stopped,   1 zombie
%Cpu(s):  1.0 us,  0.8 sy,  0.0 ni, 98.2 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
MiB Mem :   7640.2 total,    915.7 free,   5201.9 used,   1522.6 buff/cache
MiB Swap:   7863.0 total,   7863.0 free,      0.0 used.   2168.9 avail Mem 

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND                                                            
 2693 DockerU+  20   0 1333832 294436  52660 S   0.0   3.8   7:56.39 mono                                                               
 2638 DockerU+  20   0 1350504 261580  51084 S   0.7   3.3  24:35.58 mono                                                               
 2851 DockerU+  20   0 3482476 195136  66524 S   0.0   2.5   2:30.33 jackett                                                            
 2469 DockerU+  20   0 1416588 168300  37380 S   0.0   2.2   3:09.35 Plex Media Serv                                                    
 3113 DockerU+  20   0 1160956  95728  20312 S   0.0   1.2  10:45.92 qbittorrent-nox                                                    
 1127 root      20   0 1341156  91964  46676 S   0.3   1.2   0:18.43 dockerd                                                            
 1128 root      20   0  923680  82048  11692 S   0.0   1.0   1:44.79 nordvpnd                                                           
 3178 DockerU+  35  15 1267632  54788  10624 S   0.0   0.7   2:06.54 Plex Script Hos

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As you can see I only have 900GB free even if I should have only 20/25% of RAM occupied.

How can i check what it's using all this ram?

ryecoaaron · Mar 25th 2020

Why are you worried about it? Is something not working? This has been mentioned a lot on this forum. Linux uses ram to cache files. It will free up ram if it is needed.

Blabla · Mar 25th 2020

Considering that with OMV 4 I had an average usage of 25% and now it's nearly 60% I wondered if I did something wrong, maybe with ZFS.

ryecoaaron · Mar 25th 2020

Quote from Blabla

Considering that with OMV 4 I had an average usage of 25% and now it's nearly 60% I wondered if I did something wrong, maybe with ZFS.

zfs uses more ram. If you weren't using zfs on OMV 4, then I wouldn't compare the ram usage.

cabrio_leo · Mar 25th 2020

Blabla: ZFS uses the RAM as disk cache. You can control the amount of used ram: Zfs caching

Adoby · Mar 25th 2020

By default Linux uses all "unused" RAM for disk caches. Typically a simple MRU (Most Recently Used) cache.

ZFS uses a preset amount of RAM for disk caches, but uses a possibly "better" and more advanced caching algorithm than the default MRU cache. Better depending on use case, typically better in heavy use by multiple users and with plenty of RAM. ZFS keeps track of disk blocks used and implements a form of "Often Used" cache. Requires more RAM and more processing power but can in some cases achieve improved caching and better throughput.

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