I'm pretty new on linux and Proxmox world. So sorry for this noob question. But i need to use my LVM partition for my backups also but im not able to use this /dev/sda3 partition for my backups could you please help me about that?
I'm using hardware RAID1 and formatted this part as EXT4
Looks like this is an default LVM+ext4 PVE installation. With that your LVM is split into two storages. "local" (should be around 500GB I guess) as a filesystem for storing files like backups and "local-lvm" as a block storage (probably the other 1,5TB) for storing virtual disks of your VMs/LXCs and where you can't store files. So store your backups on "local". And if that isn`t big enough you got two options:
A.) backup all guests from "local-lvm", destroy your "data" thin pool, lvresize your "root" LV and extend your ext4, create a new smaller "data" thin pool using the remaining space of that VG, restore VMs/LXCs
B.) manually create a new thin volume on your "data" thin pool. Format that thin volume with a filesystem of your choice. Add an fstab entry to automount that filesystem. Add a new directory storage with content type "VZDump backups" and "is_mountpoint yes" and point it to the mountpoint of that filesystem.
