首先ISCSI性能是优于NFS的（ISCSI是基于SCSI的一种技术，属于块存储，NFS属于文件存储）

PVE挂载NFS用作虚拟机备份以及一些镜像的存储

PVE挂载ISCSI，通过lvm建立pv，vg和thin lv

thin lv挂载给虚拟机，控制器用scsi（我看原文解释scsi性能更优秀，我觉得跟sata、VirtIO在机械盘上应该没有很大差距 ）

• the SCSI controller, designed in 1985, is commonly found on server grade hardware, and can connect up to 14 storage devices. Proxmox VE emulates by default a LSI 53C895A controller.

• A SCSI controller of type VirtIO SCSI single and enabling the IO Thread setting for the attached disks is recommended if you aim for performance. This is the default for newly created Linux VMs since Proxmox VE 7.3. Each disk will have its own VirtIO SCSI controller, and QEMU will handle the disks IO in a dedicated thread. Linux distributions have support for this controller since 2012, and FreeBSD since 2014. For Windows OSes, you need to provide an extra ISO containing the drivers during the installation.

格式不可选只能raw（raw性能略优于qcow2，原文有解释，并且我简单测试过也符合这个结论）

Image Format

On each controller you attach a number of emulated hard disks, which are backed by a file or a block device residing in the configured storage. The choice of a storage type will determine the format of the hard disk image. Storages which present block devices (LVM, ZFS, Ceph) will require the raw disk image format, whereas files based storages (Ext4, NFS, CIFS, GlusterFS) will let you to choose either the raw disk image format or the QEMU image format.

• the QEMU image format is a copy on write format which allows snapshots, and thin provisioning of the disk image.

• the raw disk image is a bit-to-bit image of a hard disk, similar to what you would get when executing the dd command on a block device in Linux. This format does not support thin provisioning or snapshots by itself, requiring cooperation from the storage layer for these tasks. It may, however, be up to 10% faster than the QEMU image format. [2]

• the VMware image format only makes sense if you intend to import/export the disk image to other hypervisors.

并且这样部署支持快照

总体架构（轻喷，有不合理的地方可以指出，愿听指教）