[SOLVED] proxmox using high ram
- Thread starter Iman_V
- Start date
Can you be more specific? I don't see unusual RAM consumption.
What people most of he time miss are:
1.) "free" vs "available" RAM and interpreding htops output as "free" but it actually shows "available" RAM so that it differs from that
2.) in case ZFS is used it's ARC is by default allowed to use UP TO 50% of the hosts RAM
3.) in case "writeback" is used as as caching mode all those async writes of the guests will consume additional RAM of the host
4.) there is virtualization overhead...if you assign a VM 8GB RAM it doesn't mean it is using a maximum of 8GB. It could also use something like 10GB because of the KVM overhead
5.) when using PCI passthrough a VM will always consume the full amount of RAM you assigned to it, no matter how much the guestOS is actually using
What people most of he time miss are:
1.) "free" vs "available" RAM and interpreding htops output as "free" but it actually shows "available" RAM so that it differs from that
free -h and the webUI are reporting2.) in case ZFS is used it's ARC is by default allowed to use UP TO 50% of the hosts RAM
3.) in case "writeback" is used as as caching mode all those async writes of the guests will consume additional RAM of the host
4.) there is virtualization overhead...if you assign a VM 8GB RAM it doesn't mean it is using a maximum of 8GB. It could also use something like 10GB because of the KVM overhead
5.) when using PCI passthrough a VM will always consume the full amount of RAM you assigned to it, no matter how much the guestOS is actually using
tnx for your reply , so im new to proxmox this is my first time using it and i'm using proxmox 8 and i run 2 vm on it one debian 11 nad the other one windows server database 2022 and i have some websites running on my debian but i dont have any thing on my windows server and also on vm section it shows me that windows is using 2 or 3 gb ram and for debian almost the same but the proxmox it self is using 20 gig of my 64 gig ram by that picture that i send u and it is related to windows .
so i want to know if its usual to use this much ram or not and have can i fix this
and btw every time i turn off my windows vm it goes back to 2 or 3 gig ram usage
Without more informations like
Also keep in mind then when using the QEMU guest agent your VM summary in the PVE webUI will show "Used = total RAM - available RAM" and not "used = total RAM - free RAM". So in case you for example got a VM with 10GB vRAM and Windows is using 3GB for processes and 6 GB for caching, windows as well as PVE will report only 3 GB is being used while it's actually 9GB and htop then would show the real 9GB (or even more because of overhead) for the KVM process.
arc_summary | grep size | head -10, qm config 113 and free -h it's hard to tell you more.Also keep in mind then when using the QEMU guest agent your VM summary in the PVE webUI will show "Used = total RAM - available RAM" and not "used = total RAM - free RAM". So in case you for example got a VM with 10GB vRAM and Windows is using 3GB for processes and 6 GB for caching, windows as well as PVE will report only 3 GB is being used while it's actually 9GB and htop then would show the real 9GB (or even more because of overhead) for the KVM process.
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While not contributing to this problem, I should mention that you are not following best practices by using e1000 vNIC and IDE for your vdisk: https://pve.proxmox.com/wiki/Windows_2022_guest_best_practices
Could you verify how much RAM Windows is actually using? Especially how much of those 20GB are using by the page file cache. For example what the task manager is showing as used RAM is actually not including all the RAM that is used for caching.
Could you verify how much RAM Windows is actually using? Especially how much of those 20GB are using by the page file cache. For example what the task manager is showing as used RAM is actually not including all the RAM that is used for caching.
this is what taskmanager is showing me still no ram usage :
is this the information that u ask for or should i check something else ?
it's normal.
you need to set "Minimum memory" in you VM.
Then, when your host is at 80% RAM usage, Ballooning driver/service will inflate each guests to reduce memory to the "Minimum memory" defined.
Guest OS will delete its cached memory and Guests applications will reduce its memory because pressure from Ballooning.
you need to set "Minimum memory" in you VM.
Then, when your host is at 80% RAM usage, Ballooning driver/service will inflate each guests to reduce memory to the "Minimum memory" defined.
Guest OS will delete its cached memory and Guests applications will reduce its memory because pressure from Ballooning.
Yes, but keep in mind that ballooning won't care if the guest OS actually needs that RAM or not. It will just steal the RAM and the guest OS will have to handle this (which could mean killing processes). RAM overprovisioning should be avoided. If you assign 20GB to a VM, count those 20GB + some overhead as lost. If it needs less RAM...great...some available RAM for caching. But don'T plan to share this RAM between guests or host and guest.
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Yes, but the hard thing is to balance it. Set it too low and it might kill services instead of dropping caches. If I got a VM where applications/processes might fluctuate between 4-12 GB of RAM I can't set the "Min RAM" to lower than 12GB. I could give the VM a "Min RAM: 13GB" and "Max RAM: 20GB". Then it will probably drop 7 GB of caches. On the other hand...if the VM never needs more than 12GB I could also directly assign that VM a "Min RAM: 13GB" and "Max RAM: 13GB". 
But yes, if you got some free RAM you don't need and want to use it for guest-level caching you could add a bit to "Max RAM" so it's not wasted.
But yes, if you got some free RAM you don't need and want to use it for guest-level caching you could add a bit to "Max RAM" so it's not wasted.