ZFS can absolutely combine both into a 4TB single volume. Well like 3.78TB but you get the picture.
Note that, just like any other method which combines disks in a “RAID0” way, if one drive fails you lose everything on both drives.
But yes as others have said, “Pools” in Proxmox (or, more accurately, “Resource Pools”) are not related to storage but to permissions. A pool of VMs, of network bridges, yeah even storage but they’re not used for creating storage, only controlling access to it in an environment with lots of users (like in an enterprise).
ZFS and Ceph also use the term “Pool” but in a different context. They’re talking about a pool of combined storage, which is what you are looking for.
Put each USB disk into a ZFS vdev and then combine the two vdevs into a pool. You can add more drives into the vdev later to create mirrors within the vdev and get a RAID10-like setup once you have the means.
ZFS can absolutely combine both into a 4TB single volume. Well like 3.78TB but you get the picture.
Note that, just like any other method which combines disks in a “RAID0” way, if one drive fails you lose everything on both drives.
But yes as others have said, “Pools” in Proxmox (or, more accurately, “Resource Pools”) are not related to storage but to permissions. A pool of VMs, of network bridges, yeah even storage but they’re not used for creating storage, only controlling access to it in an environment with lots of users (like in an enterprise).
ZFS and Ceph also use the term “Pool” but in a different context. They’re talking about a pool of combined storage, which is what you are looking for.
Put each USB disk into a ZFS vdev and then combine the two vdevs into a pool. You can add more drives into the vdev later to create mirrors within the vdev and get a RAID10-like setup once you have the means.