Proxmox commits RAM than total of VMs

[sujeetkrm]

Hi, such a problem.
There are 13 VMs on total vm memory allot 545 ram
Proxmox uses show 690gb ram please help where is rest ram

#cat /proc/meminfo
MemTotal: 791259800 kB
MemFree: 76984648 kB
MemAvailable: 73975960 kB
Buffers: 8020 kB
Cached: 2055476 kB
SwapCached: 0 kB
Active: 695797584 kB
Inactive: 2044336 kB
Active(anon): 695777132 kB
Inactive(anon): 2023464 kB
Active(file): 20452 kB
Inactive(file): 20872 kB
Unevictable: 5320 kB
Mlocked: 5320 kB
SwapTotal: 0 kB
SwapFree: 0 kB
Dirty: 48 kB
Writeback: 0 kB
AnonPages: 695784720 kB
Mapped: 170736 kB
Shmem: 2024076 kB
KReclaimable: 389784 kB
Slab: 4571300 kB
SReclaimable: 389784 kB
SUnreclaim: 4181516 kB
KernelStack: 22688 kB
PageTables: 2693456 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 395629900 kB
Committed_AS: 601900672 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 4291148 kB
VmallocChunk: 0 kB
Percpu: 61696 kB
HardwareCorrupted: 0 kB
AnonHugePages: 328742912 kB
ShmemHugePages: 0 kB
ShmemPmdMapped: 0 kB
FileHugePages: 0 kB
FilePmdMapped: 0 kB
CmaTotal: 0 kB
CmaFree: 0 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
Hugetlb: 0 kB
DirectMap4k: 34646996 kB
DirectMap2M: 652890112 kB
DirectMap1G: 118489088 kB

 

[Dunuin]

In case you use ZFS the ARC will use up to 50% of your hosts RAM for caching (which won't be counted as cached RAM by linux).

 

[sujeetkrm]

arc and zfs not using ram
# arc_summary

------------------------------------------------------------------------
ZFS Subsystem Report Sat May 07 09:07:43 2022
Linux 5.4.34-1-pve 0.8.3-pve1
Machine: SPK-X-0973 (x86_64) 0.8.3-pve1

ARC status: HEALTHY
Memory throttle count: 0

ARC size (current): 2.1 % 343.9 MiB
Target size (adaptive): 25.0 % 4.0 GiB
Min size (hard limit): 25.0 % 4.0 GiB
Max size (high water): 4:1 16.0 GiB
Most Frequently Used (MFU) cache size: 80.1 % 266.3 MiB
Most Recently Used (MRU) cache size: 19.9 % 66.2 MiB
Metadata cache size (hard limit): 75.0 % 12.0 GiB
Metadata cache size (current): 0.5 % 56.5 MiB
Dnode cache size (hard limit): 10.0 % 1.2 GiB
Dnode cache size (current): 0.3 % 3.5 MiB

ARC hash breakdown:
Elements max: 129.3k
Elements current: 11.9 % 15.4k
Collisions: 29.2k
Chain max: 2
Chains: 0

ARC misc:
Deleted: 24
Mutex misses: 2
Eviction skips: 315

ARC total accesses (hits + misses): 135.5M
Cache hit ratio: 100.0 % 135.4M
Cache miss ratio: < 0.1 % 50.5k
Actual hit ratio (MFU + MRU hits): 99.9 % 135.3M
Data demand efficiency: 100.0 % 51.6M
Data prefetch efficiency: 63.3 % 88.2k

Cache hits by cache type:
Most frequently used (MFU): 65.5 % 88.7M
Most recently used (MRU): 34.5 % 46.7M
Most frequently used (MFU) ghost: < 0.1 % 39.7k
Most recently used (MRU) ghost: < 0.1 % 2.0k
Anonymously used: < 0.1 % 38.0k

Cache hits by data type:
Demand data: 38.1 % 51.6M
Demand prefetch data: < 0.1 % 55.9k
Demand metadata: 61.8 % 83.7M
Demand prefetch metadata: 0.1 % 95.4k

Cache misses by data type:
Demand data: 20.7 % 10.5k
Demand prefetch data: 64.1 % 32.3k
Demand metadata: 5.4 % 2.7k
Demand prefetch metadata: 9.8 % 4.9k

DMU prefetch efficiency: 72.9M
Hit ratio: 1.3 % 917.6k
Miss ratio: 98.7 % 72.0M

 

[LnxBil]

There are 13 VMs on total vm memory allot 545 ram

a VM needs more ram than just the ram you gave the VM. Every emulated devices, emulated caches etc. "cost" also memory. Depending on the VMs that can be in the low 1-digit percent margin from your VM total ram. If you also use caching for disks, it is much more.

You have do not use hugepages, therefore you use 2.5 GB of page tables. Your PVE itself uses also memory und so on.

 

[leesteken]

How do you count the memory usage? Do you count the filesystem cache inside the VM? Can you tell us the numbers for all 13 VMs from Proxmox and from within the VMs?
Have you search the forum on memory usage and differences between Proxmox and inside VMs? I what way do they not apply to your situation?