Memory usage empty PVE hosts

C

CS-

New Member
Apr 3, 2025
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Is it normal that empty PVE hosts take up to 11% memory usage?
My hosts have 125,57GiB and 13,55 GiB is already in use without any VMs on it.
I already found a few "consumers", but I can't explain the entire 13,55 GiB

ZFS ARC: 1,3 GiB
RSS: 4,3 GiB
SLAB: 1,2GiB

Still ~6GiB that I can't explain. Could it be that this is reclaimable kernel memory that doesn't show up correctly?

Any advice is welcome.

Thanks in advance.
 
CS- said:
Is it normal that empty PVE hosts take up to 11% memory usage?
My hosts have 125,57GiB and 13,55 GiB is already in use without any VMs on it.
I already found a few "consumers", but I can't explain the entire 13,55 GiB

ZFS ARC: 1,3 GiB
RSS: 4,3 GiB
SLAB: 1,2GiB

Still ~6GiB that I can't explain. Could it be that this is reclaimable kernel memory that doesn't show up correctly?

Any advice is welcome.

Thanks in advance.
Click to expand...
What's the output of free -h on the web shell?
 
I'd also like to see
Bash: 
top -em -co%MEM
slabtop -osc | head -n60
zarcsummary | less
The PVE GUI shouldn't include cache (Aside from ARC) in the Summary's RAM usage statistic.
Did you add any custom sysctls?
 
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Simply put, you're putting too much thought into this.

The server isn't even running VMs, and some of the RAM is being used by the kernel for caches and the like. You're not getting anything OOM-killed and it's not running short on resources, so put it out of your mind. There are bigger issues in the world.
 
free -h
total used free shared buff/cache available
Mem: 125Gi 13Gi 112Gi 75Mi 623Mi 112Gi
Swap: 0B 0B 0B
 
top - 10:40:15 up 3 days, 15:55, 1 user, load average: 0.22, 0.18, 0.13
Tasks: 863 total, 1 running, 862 sleeping, 0 stopped, 0 zombie
%Cpu(s): 0.1 us, 0.1 sy, 0.0 ni, 99.8 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
MiB Mem : 128586.1 total, 115342.3 free, 13561.2 used, 623.3 buff/cache
MiB Swap: 0.0 total, 0.0 free, 0.0 used. 115024.8 avail Mem

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1718 root 20 0 5260.5m 1.6g 1.5g S 0.3 1.3 60:57.23 falcon-sensor-bpf
1496387 www-data 20 0 289.5m 215.4m 14.9m S 0.0 0.2 0:09.83 pveproxy worker
2837 root rt 0 577.9m 194.7m 51.3m S 4.0 0.2 202:08.41 /usr/sbin/corosync -f
1496385 www-data 20 0 245.0m 170.1m 12.9m S 0.0 0.1 0:08.60 pveproxy worker
3096 www-data 20 0 229.7m 170.1m 21.4m S 0.0 0.1 0:07.99 pveproxy
1496386 www-data 20 0 244.9m 167.8m 10.6m S 0.0 0.1 0:08.79 pveproxy worker
1042372 root 20 0 240.3m 159.5m 7.7m S 0.0 0.1 0:13.00 pvedaemon worker
1572355 root 20 0 239.9m 158.6m 7.2m S 0.0 0.1 0:02.06 pvedaemon worker
1669883 root 20 0 239.4m 157.4m 6.7m S 0.0 0.1 0:00.15 pvedaemon worker
3057 root 20 0 228.4m 151.4m 3.8m S 0.0 0.1 0:05.16 pvedaemon
3127 root 20 0 210.7m 127.1m 4.1m S 0.0 0.1 0:22.68 pvescheduler
3071 root 20 0 214.9m 126.7m 6.3m S 0.0 0.1 0:34.70 pve-ha-crm
3116 root 20 0 214.0m 125.7m 6.4m S 0.0 0.1 0:58.76 pve-ha-lrm
2966 root 20 0 198.1m 124.5m 10.0m S 0.0 0.1 24:29.60 pvestatd
2964 root 20 0 187.8m 112.5m 6.7m S 0.0 0.1 10:16.51 pve-firewall
1036 root 20 0 129.7m 75.0m 73.3m S 0.0 0.1 0:15.03 /usr/lib/systemd/systemd-journald ....
.....
 
slabtop -osc | head -n60
Active / Total Objects (% used) : 4583972 / 4964347 (92.3%)
Active / Total Slabs (% used) : 94068 / 94068 (100.0%)
Active / Total Caches (% used) : 369 / 465 (79.4%)
Active / Total Size (% used) : 796643.95K / 889945.07K (89.5%)
Minimum / Average / Maximum Object : 0.01K / 0.18K / 16.00K

OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME
1924288 1923865 99% 0.06K 30067 64 120268K dmaengine-unmap-2
117792 115803 98% 1.00K 3681 32 117792K iommu_iova_magazine
6316 6314 99% 8.00K 1579 4 50528K kmalloc-rnd-12-8k
2322 2238 96% 16.00K 1161 2 37152K zio_buf_comb_16384
16768 3983 23% 2.00K 1048 16 33536K kmalloc-cg-2k
347340 345674 99% 0.09K 8270 42 33080K kmalloc-rnd-08-96
389872 387291 99% 0.07K 6962 56 27848K vmap_area
1298 1285 98% 12.25K 649 2 20768K task_struct
21280 20854 97% 0.91K 608 35 19456K dnode_t
2324 2301 99% 8.00K 581 4 18592K kmalloc-rnd-10-8k
32060 31786 99% 0.57K 1145 28 18320K radix_tree_node
93912 91919 97% 0.19K 2236 42 17888K dentry
25380 22025 86% 0.67K 540 47 17280K proc_inode_cache
14877 14851 99% 1.08K 513 29 16416K zfs_znode_cache
44352 21824 49% 0.36K 1008 44 16128K dmu_buf_impl_t
97950 96515 98% 0.13K 3265 30 13060K kernfs_node_cache
50694 15379 30% 0.23K 1491 34 11928K arc_buf_hdr_t_full
120498 120312 99% 0.09K 2869 42 11476K kmalloc-rnd-03-96
21408 17740 82% 0.50K 669 32 10704K kmalloc-rnd-14-512
16065 15713 97% 0.62K 315 51 10080K debugfs_inode_cache
15158 14977 98% 0.60K 286 53 9152K inode_cache
15168 14888 98% 0.50K 474 32 7584K kmalloc-rnd-11-512
72266 70224 97% 0.09K 1571 46 6284K lsm_inode_cache
8685 8623 99% 0.71K 193 45 6176K 0000:0f:00.0-mlx5_fs_ftes
5216 5114 98% 1.00K 163 32 5216K kmalloc-rnd-14-1k
5184 5111 98% 1.00K 162 32 5184K kmalloc-rnd-08-1k
5184 4834 93% 1.00K 162 32 5184K kmalloc-rnd-07-1k
53634 14386 26% 0.09K 1277 42 5108K abd_t
4608 4556 98% 1.00K 144 32 4608K kmalloc-rnd-13-1k
20874 18726 89% 0.19K 497 42 3976K vm_area_struct
984 814 82% 4.00K 123 8 3936K kmalloc-rnd-10-4k
7712 5503 71% 0.50K 241 32 3856K kmalloc-rnd-06-512
15200 15089 99% 0.25K 475 32 3800K sa_cache
888 433 48% 4.00K 111 8 3552K kmalloc-cg-4k
10812 6978 64% 0.31K 212 51 3392K bio-264
1590 1389 87% 2.06K 106 15 3392K sighand_cache
198 177 89% 12.00K 99 2 3168K zio_buf_comb_12288
792 554 69% 4.00K 99 8 3168K zfs_btree_leaf_cache
3104 1034 33% 1.00K 97 32 3104K kmalloc-cg-1k
2752 2714 98% 1.00K 86 32 2752K kmalloc-1k
349696 345369 98% 0.01K 683 512 2732K kmalloc-rnd-07-8
5408 5061 93% 0.50K 169 32 2704K kmalloc-rnd-07-512
85760 7666 8% 0.03K 670 128 2680K kmalloc-rcl-32
830 376 45% 3.00K 83 10 2656K zio_buf_comb_3072
3486 3208 92% 0.75K 83 42 2656K shmem_inode_cache
27510 26844 97% 0.09K 655 42 2620K kmalloc-rnd-05-96
320 247 77% 8.00K 80 4 2560K kmalloc-cg-8k
10176 9648 94% 0.25K 318 32 2544K kmalloc-rnd-13-256
150 140 93% 16.00K 75 2 2400K lz4_cache
300 159 52% 8.00K 75 4 2400K zio_buf_comb_8192
12516 12450 99% 0.19K 298 42 2384K kmalloc-rnd-15-192
71040 70823 99% 0.03K 555 128 2220K kmalloc-rnd-12-32
1088 1082 99% 2.00K 68 16 2176K kmalloc-rnd-10-2k
 
ZFS Subsystem Report Fri Sep 11 10:42:15 2026
Linux 7.0.14-12-pve 2.4.3-pve1
Machine: nsbehapve209 (x86_64) 2.4.3-pve1

ARC status:
Total memory size: 125.6 GiB
Min target size: 3.1 % 3.9 GiB
Max target size: 10.0 % 12.6 GiB
Target size (adaptive): 6.5 % 12.6 GiB
Current size: 6.5 % 838.2 MiB
Free memory size: 112.7 GiB
Available memory size: 108.5 GiB

ARC structural breakdown (current size): 838.2 MiB
Compressed size: 42.4 % 355.5 MiB
Overhead size: 53.5 % 448.4 MiB
Bonus size: 0.5 % 4.5 MiB
Dnode size: 2.2 % 18.0 MiB
Dbuf size: 0.9 % 7.3 MiB
Header size: 0.4 % 3.2 MiB
L2 header size: 0.0 % 0 Bytes
ABD chunk waste size: 0.1 % 1.2 MiB

ARC types breakdown (compressed + overhead): 804.0 MiB
Data size: 83.2 % 669.2 MiB
Metadata size: 16.8 % 134.7 MiB

ARC states breakdown (compressed + overhead): 804.0 MiB
Anonymous data size: < 0.1 % 136.0 KiB
Anonymous metadata size: < 0.1 % 258.0 KiB
MFU data target: 36.3 % 291.5 MiB
MFU data size: 36.4 % 292.7 MiB
MFU evictable data size: 20.6 % 165.2 MiB
MFU ghost data size: 0 Bytes
MFU metadata target: 12.4 % 100.0 MiB
MFU metadata size: 3.4 % 27.7 MiB
MFU evictable metadata size: 0.4 % 3.0 MiB
MFU ghost metadata size: 0 Bytes
MRU data target: 38.9 % 312.5 MiB
MRU data size: 20.8 % 167.4 MiB
MRU evictable data size: 7.8 % 62.7 MiB
MRU ghost data size: 0 Bytes
MRU metadata target: 12.4 % 100.0 MiB
MRU metadata size: 13.3 % 106.8 MiB
MRU evictable metadata size: 1.6 % 12.8 MiB
MRU ghost metadata size: 0 Bytes
Uncached data size: 26.0 % 209.0 MiB
 
Please use code blocks. This is unreadable as the formatting/indentation is lost and I can't reliably interpret the output.
I forgot to mention, cat /proc/meminfo might also be interesting.
 
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