clone failed: can't lock file

We use Proxmox API for parallel full clones of same or different template from "nfs volume1" to target storage is "nfs volume 2" . no of parallel : 20 to 30 clones at a time. we experience below error. Is there any way to solve the issue? create full clone of drive scsi0...

So I tried to store my vm in a storage I created inside my zfspool as dataset and add it as a directory storage in proxmox called vm-data, This caused an error: clone failed: can't lock file '/var/lock/pve-manager/pve-storage-vm-data' - got timeout But doesn't happen if I use my zfspool storage...