Why Does Proxmox Show So Much Memory In Use?

forbin

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Dec 16, 2021
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My PVE 7 server has 1 TB RAM. There are only 6 guests running. 4 of them have 16 GB RAM each, the other 2 have 2 GB RAM each. That works out to 68 GB total. Why does the summary screen in ProxMox show 452 GB RAM in use?
 

Dunuin

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Jun 30, 2020
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I guess you use ZFS. The ARC will use up to 50% of your RAM for caching by default. Search the Proxmox Wiki on how to limit the ARC size.
 
Last edited:

forbin

New Member
Dec 16, 2021
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I guess you use ZFS. The ARC will use up to 50% of your RAM for caching by default. Search the Proxmox Wiki on how to limit the ARC size.
That is exactly right, I do use zfs! It's okay with me if zfs uses lots of ram for the ARC as long as it releases it when apps or VMs need it. Is that the expected behavior?
 

Dunuin

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Jun 30, 2020
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That is exactly right, I do use zfs! It's okay with me if zfs uses lots of ram for the ARC as long as it releases it when apps or VMs need it. Is that the expected behavior?
Yes, the ARC should shrink when RAM is needed. But if too much RAM is needed too fast, ZFS may have problems to free up the RAM in time. In such a case it might make sense to limit the ARC.
 

sienar

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Jul 19, 2017
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Anyone know if Proxmox GUI will ever be updated to properly show that the ARC memory is buffer and is not the same as "in use"? HTOP shows it that way, with ARC usage colored the same as other buffers. You can even add ARC specific counters to the display in HTOP. I feel like with how heavily integrated ZFS is in Proxmox, the GUI should pull out those stats.
 

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