I've looked through this forum for an answer to my current question, but everything is only tangentially related; that is, I'm trying to determine the highest possible number to use for the --transfers option from my SSD to an external USB flash drive, but all the other threads discuss possible maximums for uploading to a cloud service and not locally syncing folders.
I imagine there is some testing I can do to determine the I/O speeds of the flash drive itself, but I'm not really sure where to start there and didn't want to reinvent the wheel if someone else has already trialed-and-errored this. I am currently using rclone sync /local/folder /media/usb -P -u --transfers 64 but am wondering if that's "best."
every system is different, all the more so with external usb drives.
run the same command a few times, changing the value for --transfers
then you will know.
and that is an old version of rclone, really should update.
Such drives are painfully slow, especially for parallel random writes. IMO you will see much better results with default transfers value.
In general there is no universal answer for your question - all depends on exact hardware/software environment and nature of your transfers. In most cases using defaults is good enough. There is no need to try to solve problem which does not exist.
I didn't even think the rclone in Fedora would be so out-of-date, so it didn't dawn on me to update it separately.
My hope is to minimize the amount of time the sync took so I could run it as a script at reboot or shutdown to guarantee the files were always backed up. I've also considered toying with lsyncd but don't know much about it.
I just played around a bit with different --transfers options and found exactly what you suggested, kapitainsky: no real difference between default and higher numbers... Literally a 2.6 second difference.
