Proxmox high RAM usage

[potato_sips]

I’m currently running a Proxmox PC with 16GB of RAM. This system hosts 2 VMs and 1 LXC.

• VM-1: This VM is allocated 6GB of RAM and runs Jellyfin along with other ARR projects.
• VM-2: This VM is allocated 10GB of RAM and is used for a Minecraft server. Note that the Minecraft server is assigned 6GB of RAM.

However, I’m facing an issue where my Proxmox server is using almost all of its RAM (around 14GB out of 16GB), as shown in the Proxmox RAM status. But the RAM usage inside the VMs tells a different story:

• VM-1 (Debian 12) is using 2.15GB out of 6GB. image || vm config
• VM-2 (Debian 12) is using 7.3GB out of 10GB. image || vm config
• The LXC, which just contains Caddy, uses around 50MB of RAM.

So, according to my calculations, the total RAM usage should be around 11GB (Proxmox 1.5GB + VM-1 2.15GB + VM-2 7.3GB). I’m unable to account for an extra 2GB of usage. Moreover, sometimes the Proxmox webUI status shows 15.5GB RAM usage, so I’m unsure what’s using the leftover 3/4GB of RAM. This issue is causing other applications inside all VMs to sometimes not respond.
For reference, here’s what I’m running in my VMs (all are Docker containers):

• VM-1: [VM1 Docker Containers]
• VM-2: [VM2 Docker Containers]

My Proxmox PC configuration is as follows:

• CPU: i5-4590 (4c 4t)
• RAM: 8*2 1333hz DDR3
• Motherboard: Gigabyte H81
• Drive: 120GB SSD for boot & 12TB HDD for storage

I’m looking for a solution to this issue. Any help would be greatly appreciated. Thanks in advance!

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[leesteken]

This kind of questions has been answer so many time over already. Your VMs can use up to 16GB (which is too much because Proxmox also needs 2GB) and according to Proxmox they are using all that memory. The operating systems inside the VM will show filesystem cache as unused (because it can be reused for something else inside the VM immediately) but Proxmox does not know this and cannot use that memory. Each time you cannot account for memory, it's "hidden" filesystem cache.

 

[potato_sips]

This kind of questions has been answer so many time over already. Your VMs can use up to 16GB (which is too much because Proxmox also needs 2GB) and according to Proxmox they are using all that memory. The operating systems inside the VM will show filesystem cache as unused (because it can be reused for something else inside the VM immediately) but Proxmox does not know this and cannot use that memory. Each time you cannot account for memory, it's "hidden" filesystem cache.

very well then
guess i have to install debian bare-metal
thanks for the rply

 

[leesteken]

guess i have to install debian bare-metal

Or just give the VMs 5GB and 9GB. You can also save on the VM overhead by running both as containers (since they are Linux VMs).

 

[Dunuin]

5GB and 9GB

More like 4GB + 8GB or better buying more RAM. Don't forget he is also running a LXC where he probably assigned more than the 50MB for RAM and there is overhead of the KVM processes and maybe even stuff like writeback enabled.

 

[LnxBil]

This kind of questions has been answer so many time over already.

We REALLY need a page in the documentation or the Wiki that explaints what's happending behind the scenes .. even if it's only a link list to all the threads with proper explanations.