The zpool is local for me so how do i make the zpool go NFS and then mount the NFS in VM?
You basically want your Proxmox to be a NAS so it can securely store files and share them on your LAN. But Proxmox can't do that by itself if you want a GUI. So one option would be to use the drives with ZFS on your Proxmox host itself. But that way you need to use CLI to setup, monitor and manage everything because that stuff isn't implemented in the Proxmox WebGUI. But you could install another GUI like Webmin or Cockpit to help you a little bit.
My favorite option would be to create a NAS VM where you install the NAS OS of your choice (I use FreeNAS/TrueNAS which is also using ZFS) so you got a nice GUI. If you got a free PCIe 8x slot you can use a PCIe HBA card and attach HDDs to it. If you then enable PCI passthrough (and your hardware supports this) you can passthrough the complete HBA card with all drives attached to it into the NAS VM, so the NAS OS can access that drives physically without any virtualization overhead. But if you passthrough something into a VM that hardware can't be used anymore on the host or on other VMs. So you would need some other drives (durable SSDs prefered) that are directly connected to your mainboard and not passed through so you can install Proxmox on it and run all VMs from it. Only option to access stuff on the HDDs then would be to use network protocols like NFS/SMB/iSCSI/FTP/WebDAV/SSH and so on.
With the user data replication you have another node in a cluster and the data is synced between them that way?
I've got two FreeNAS server but the same thing also works with Proxmox. Both OS are using the same native ZFS commands ("zfs send | zfs receive") to replicate stuff from one pool to another pool. Look here for
zsync and
pvesr. If you are using FreeNAS it is way easier to setup the replication because everything is build into the GUI.
if i use the proxmox backup server and use snapshot of VM. Then only new change will be backed up right and no downtime on VM. aint snapshot good enough?
Not sure if PSB supports incremental backups meanwhile. I know they wanted to implement that but last time I tried it, it wasn't ready.
If "snapshot" as backup mode is good enough depends on your needs. "stop" is always more secure, because the VM will be shutdown first so everything is securely stored on the drives, no software is running and everything is in a defined state.
If you are using "snapshot" as backup mode you are just saving the state of the disks while it is running and not the RAM, not the state of running processes and not stuff that is in the cache and waits to be written to the disk. But with the last one I'm not totally sure. Could be possible that Proxmox tells the VM to finish async writes. If you later want to restore a VM from a backup that was created with "snapshot" mode, it is like you pulled out the power plug while the VM was running and everything crashed. So you are booting into a crashed VM that wasn'T shutdown properly. That might be fine most of the times but I wouldn't rely on it, especially if that VMs are storing important stuff you don't want to loose.
And if you are not using PBS but want VM backups, it won't be incremental. So if you got a 10TB VM, each backup will store the complete 10TB VM again and again.