EDIT: Sorry, I misunderstood this question ~~ I have a raspberry pi connected to a 1 TB SSD. This has the following cron job:

00 8 * * * /usr/bin/bash /home/user/backup/backup.sh

And the command in backup.sh is:

rsync --bwlimit=3200 -avHe ssh user@instance-ip:/var/www/mander/volumes /home/user/backup/$(date | awk '{print $3"-" $2 "-"$6}')

In my case, my home network has a download speed of 1 Gbps, and the server has an upload speed of 50 Mbps, so I use -bwlimit=3200 to limit the download to 25.6 Mbps, and prevent over-loading my server's bandwidth.

So every morning at 8 am the command is run and a full backup copy is created.

It seems that you have a different problem than me. In your case, rather than doing a full copy like me, you can do incremental backups. The incremental backup is done by using rsync to synchronize the same folder - so, instead of the variable folder name $(date | awk '{print $3"-" $2 "-"$6}'), you can simply call that instance_backup. You can copy the folder locally after syncronizing if you would like to keep a record of backups over a period of a few days.

On a second thought, I would also benefit from doing incremental backups and making the copies locally after synchronizing... ~~