Enabling Balloning the proxmox host reach 75% swap usage

[openaspace]

Hello,
this morning the main vps machine in the proxmox host was really slow... looking the host informations I see that the swap space was used for the 75% (8gb size)! .

The vps (10gb of ram on 16 available from the host) was completely slow, i have powered off the vps and set the balloning to off.

Now I see that the host swap usage is only 20%.

The vps now appear to be fast and network throughput is normal.

What I can do to stabilize this situation?
I'm not using zfs, it run on a raid 10 ext4.

Thank you.

 

[openaspace]

In other host I'm using more ram of the first host and there is not swap usage, but instead ksm sharing.
(this host use zfs)