I've been running rclone for a number of years on an original 2012 Model 1 Raspberry Pi B+ running Raspbian Jessie . It acts as an rsync server for my home network, , once a week it clones one USB drive to another , then once a month backs the backups to dropbox.
It had been working fine , but I noticed around October 2022 it was failing to complete, the process getting killed on the Pi. Running with the -vv flags it seemed to fail somewhere in an Mac iPhoto directory structure, which was itself getting synced via iCloud independently. I didn't get an error in the logs. The file structure is complex at this point, and I'd also been taking some videos on my phone which were generating some large files, and I decided the first thing was to upgrade to rclone 1.61.1. This didn't really change things beyond the fact that now the RPi would freeze at the point of failure, with no obvious error in the log. reading similar posts, it looked like the RPi was not coping with running out of memory. I have swap disabled as swapping to an SSD is not a great idea. All non-essential services were disabled (sound, HDMI it runs headless). I replaced the microsd card and reflashed this with the latest legacy OS for this model (Buster) but still no change.
I tried various configurations suggested in these forums designed to enable small memory footprint machines. In my case time taken is not an issue, I'm happy if the backup takes a long time, I just need it to complete
I found that this combination of parameters allowed rclone to run to completion on this aged small footprint machine and I have been using this since reliably
rclone sync --dropbox-chunk-size 5Mi --transfers 1 --max-backlog 100 --tpslimit=9 --use-mmap --buffer-size=0 --exclude-from /etc/exclude.txt {from} Dropbox:{to}