Decrease backup size


New Member
Feb 8, 2023
Hello Proxmox experts,

I have TrueNAS VM installed on my HP Server running Proxmox VE, this VM have 4 HDD size 900Gb associated using passthrough and here no problems. My problem is that I tried to create the backup of this VM on an external HDD but I noticed when the job is running, the backup size is 3.3Tb. Of course I know that the backup is compressed and this is not the real size of the backup, but I had an error from the job that says "no space left on the device". On my external HDD I have more that 950Gb available, so my question is, is there a way to tell to proxmox to backup only the configuration of the VM and the main HDD where TrueNAS OS is running? In this way I think that backup size could decrease a lot. Is that correct?
Any suggestions are welcome :)

if you don't want to back-up all disks, you can edit the others in the VM's Hardware UI and unselect the Backup checkbox in the advanced disk settings.
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