Server in kvm virtual machine possible?

I’m currently trying to run the server in a kvm virtual machine on a Proxmox server. The vm uses a NFS share for backup.
Is this an acceptable approach or should I better install the server on bare metal and on a dedicated machine?

My observation is that the server is extremly challenging with regards to disc io, which has probably sigificant impact on the performance of other vms. The cpu has most of the time moderate workload due to the fact, that she is waiting for io. IO delay is between 30 and 65%.

  1. how can the backup create 3 times more metadata files than files to backup? Is this correct?
  2. Saving metadata takes quite a big proportion of the entire backup? Is this correct?
  3. Would it be better to dedicate a standlone machine to backup and how much RAM is recommended?

Sharing your thoughts, experience and advice with is much appreciated.