Backup strategy idea, to clear Proxmox storage

[eiger3970]

I need to manage my Proxmox disk storage, which often fills up with automatic Proxmox daily backups to the Proxmox disk.
My idea is to create a cron script, to rsync the latest backup (daily on Proxmox) weekly to another machine. If the transfer to machine2 is successful (machine2 may be turned off), then delete all the backups to make space on the Proxmox disk.

I was using FreeNAS on machine3, but I ran a BIOS shutdown after the transfer, then turn on for the transfer, but the BIOS or hardware was unreliable so I'm scrapping FreeNAS and using the machine for something else.

Any comments on that?

 

[eiger3970]

So, I need to finalise backups, which have been turned off, as my disks fill up, then Proxmox freezes with i/o errors.
Current setup:
4 x 120 GB Intel SSDs. (some have said these server grade drives need no RAID, so I'm open to feedback)
Zfs

# zpool status
  pool: rpool
state: ONLINE
  scan: resilvered 8.43G in 0h1m with 0 errors on Thu Jun 21 20:05:29 2018
config:

    NAME        STATE     READ WRITE CKSUM
    rpool       ONLINE       0     0     0
      mirror-0  ONLINE       0     0     0
        sda2    ONLINE       0     0     0
        sdb2    ONLINE       0     0     0
        sdc2    ONLINE       0     0     0
        sdd2    ONLINE       0     0     0

# zfs list
NAME                       USED  AVAIL  REFER  MOUNTPOINT
rpool                     21.3G  86.2G    96K  /rpool
rpool/ROOT                6.97G  86.2G    96K  /rpool/ROOT
rpool/ROOT/pve-1          6.97G  86.2G  6.97G  /
rpool/data                5.68G  86.2G    96K  /rpool/data
rpool/data/vm-141-disk-1    64K  86.2G    64K  -
rpool/data/vm-142-disk-1  4.73G  86.2G  4.73G  -
rpool/data/vm-143-disk-1    64K  86.2G    64K  -
rpool/data/vm-144-disk-1    64K  86.2G    64K  -
rpool/data/vm-145-disk-1   973M  86.2G   973M  -
rpool/data/vm-146-disk-1    64K  86.2G    64K  -
rpool/data/vm-148-disk-1    64K  86.2G    64K  -
rpool/data/vm-149-disk-1    64K  86.2G    64K  -
rpool/swap                8.50G  94.3G   481M  -

I am thinking of changing the RAID10 on the 4 disks, to RAIDZ on 3 disks. The 4th disk is then spare for backups.
I need to ensure my disks have automatic backups, but don't fill up the disks so Proxmox stops working.

I then need to rsync backups to another machine, but that's another story.
Machine two doesn't always turn on with the BIOS alarm clock, then off after rsync.

Question: I'm unsure if this is the best storage and backup management.
I'm unsure how to change the RAID on the existing setup. Worried I will lose Proxmox and it's setup.
Anyone wondering, I'm planning the change the VMs to containers, which should be a lot smaller and more efficient.