Node RAM usage is high

It seems like Node is using a lot of RAM. Do you know why? This time, a new node was added, and the memory usage of the existing node increased significantly…
(synology ds1821+ 20g ram)

Yes. Because your disk is too slow.
Either optimize your disk setup (eliminate SMR, USB and network storages, especially VMs and bloated FS like ZFS or BTRFS without a special device on SSD, or using of exFAT) or add more RAM.
Unfortunately there is not much other solutions right now.

It’s ext4 and there was no problem before, but I think there was a problem because I added a new node this time. If the problem continues, I should not install additional nodes.

Then please provide your stats.
For example, the bare metal Windows setup, the RAM usage:


and for the docker nodes:

CONTAINER ID   NAME           CPU %     MEM USAGE / LIMIT     MEM %     NET I/O           BLOCK I/O   PIDS
3d20fef76e67   storagenode5   4.44%     1.015GiB / 24.81GiB   4.09%     275GB / 43.3GB    0B / 0B     349
9fb28e5cf48a   storagenode2   6.10%     208.6MiB / 24.81GiB   0.82%     1.1GB / 50.9GB    0B / 0B     53
CONTAINER ID   NAME              CPU %     MEM USAGE / LIMIT     MEM %     NET I/O           BLOCK I/O   PIDS
83a64c88f103   storagenode2      21.02%    860.3MiB / 31.32GiB   2.68%     5.77GB / 235MB    0B / 0B     0
46acaa9dc01b   storagenode       10.13%    12.48GiB / 31.32GiB   39.84%    2.73GB / 331MB    0B / 0B     0

I do not know. But some believes that less RAM usage is better…
However, regarding storagenodes I still think that the success rate is better. What’s the point to calc how much my node used, if it’s able to serve 99% requests on the not fully used HW?