I'm running a 3 node Proxmox cluster with standard ceph installation (2 nodes with osds, 1 node only as quorum). I do backups with https://github.com/EnterpriseVE/eve4pve-barc and after the backup my vms randomly hang. I tried both (cache=writeback, cache=writethrough) without any difference. What's the correct setting and how to avoid the issue?