RAM summary usage is not equal to the sum of allocated memory
- Thread starter alpot
- Start date
Can you share a few more details? For example, which summary shows 46 GiB? The one in the node summary?
Keep in mind that other services on the host also need memory. For example the whole management stack that handles the guests, provides the API and web UI and so forth. So you are likely to see a bit higher memory usage on the host itself than what you allocated to each guest.
Unless there are features triggering that reduce and/or consolidate RAM usage, like KSM (where memory pages of VMs that contain the same data are merged) or Memory ballooning (where the guest can return memory to the host if not needed, needs you to configure a lower min memory in the VMs memory setting).
Keep in mind that other services on the host also need memory. For example the whole management stack that handles the guests, provides the API and web UI and so forth. So you are likely to see a bit higher memory usage on the host itself than what you allocated to each guest.
Unless there are features triggering that reduce and/or consolidate RAM usage, like KSM (where memory pages of VMs that contain the same data are merged) or Memory ballooning (where the guest can return memory to the host if not needed, needs you to configure a lower min memory in the VMs memory setting).
The host has a total of 64GB.
There are 6 VMs running with the following memory allocation. Ballooning and KSM are enabled, and the Min memory is equal to the allocated memory.
VM1 - 4GB
VM2 - 6GB
VM3 - 4GB
VM4 - 16GB
VM5 - 2 GB
VM6 - 12GB
So that's a total of 44GB. But the summary shows usage of 46.25GB out of 60GB (4GB is already reserved by the host, I believe)
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If you see 4GiB less of memory in the node summary, then they are used for something else. But Proxmox VE won't be able to use them.
So overall, another ~2 GiB of memory used doesn't surprise me too much.
Regarding the mismatch of seeing 60GiB of RAM our of the 64 installed: Is there maybe an integrated GPU in this machine that gets some of the memory allocated? Usually that can be configured in the BIOS.
Because that is also what I have on my workstation here in our office. Out of the 128 GiB installed, I have ~124GiB usable in the node summary.
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Every AM5 CPUhas integrated graphics (but maybe it can be disabled?). I have an AM4 without integrated graphics and 128GiB of memory but PVE 9.1 reports 125.78GiB.
The Linux kernel reserves some memory (per CPU core/thread, so this differs between systems), which I think explains why every GNU/Linux system always reports a little less.
QEMU/KVM takes some memory for emulation of virtual devices and for the virtual display also (10-100MiB per VM). The manual also states that Proxmox itself needs about 2GB of memory.
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Hmm.. I thought the 4 GiB was already reserved for the OS, Proxmox services, and emulation, which is why it is no longer accessible, and the remaining are for VMs to use.
Unlike ESX, PVE is
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If you allow me some comment here
That classification regarding type1/2 hypervisors is a very strict approach that does not do justice to the nuances that have come up since it was coined back in the 1970s.
See this quote from that same wiki article: