Memory usage statistics

[vladsams]

Proxmox VE 6.1
Cluster, 2 nodes absolutely identical in configuration and hardware.
node1 - 1 VM, linux.
node2 - 3 VMs, all linux.

Proxmox Summary pages for both nodes shows:
node1 RAM usage 26 Gib of 31.
node2 RAM usage 17 Gib of 31.

However, summarizing separately values of VSZ and RSS columns in 'ps aux' output on each node i get:
node1
MEMVSZ_TOTAL: 23 Gib
MEMRSS_TOTAL: 11 Gib
node2
MEMVSZ_TOTAL: 36 Gib
MEMRSS_TOTAL: 16 Gib

It make sense because at least there are more VMs on node2, than on node1, and they use more memory.
But this does not match proxmox statistics, which shows that memory usage is much greater for node1, not node2.

Questions are:
1. Where from proxmox takes its statistics?
2. Is it correct to evaluate used memory based on 'ps aux' output? If it is correct than why proxmox statistics absolutely do not match 'ps' statistics?

 

[Stefan_R]

This can happen from caches that appear as "used" memory, but not in 'ps' output. Use 'free -h' to see RAM stats on the command line. If you use ZFS, you can also check 'arcstat' to see the size of the ARC.