I recently purchased a Dell R730. My plan was to run a few VMs, and use the 8 drive bays as a a large RAID array. I have been getting to know Proxmox, which i dont really have any complaints about, over the past few months. I currently have 4 8TB drives set up in a ZFS pool in a TrueNAS core VM. It has become full. Last night I went to expand the pool capacity and I find out that its not possible to just add a drive. So now ive been reading about UnRaid, which has that capability. I think i know the right thing to do, but i wanted to hear other peoples opinions on the matter. Should i start fresh with a bare metal unraid install, or should i run unraid as a VM in Proxmox? Im kind of disappointed that truenas pools cannot be easily expanded as i just spent a few months working kinks out with proxmox and truenas
This isn't a limitation of TrueNAS, but rather of ZFS itself. A new ZFS feature that allows expanding the pool one drive at a time has been in the works for a long time now and is supposed to be rolling out really soon (as it has been for the past 2-3 years I think), but as of right now it can't be done on any NAS solution that uses ZFS.
As you noted, UnRAID can do it - because it uses a different kind of data+parity system (you can continue to add a drive at a time as long as the largest drive has your parity data, I think). If you were comfortable running TrueNAS in a VM then you should have no problem running UnRAID the same way. In fact, it will probably be faster just because it's less resource intensive (and certainly less RAM intensive than ZFS)