VM becomes unresponsive during Veeam backup

When a Veeam backup job runs against a VM on our HDD-backed Ceph cluster, the VM becomes unresponsive partway through the backup. In some cases, it recovers automatically once the job completes. Sometimes, it requires a hard reset to come back online. We have reproduced this across multiple VMs, and it appears to affect only our HDD-based clusters. Backups using Proxmox Backup Server from the same…