rsync as a background process?

Question

I've been using rsync to sync a bunch of files between my two servers. I set a cron job that would run rsync every minute. However, I'd prefer if I could have it run always, so that files are synced the moment they are changed. What would be the best way to do this?

Thanks.

Answer 1

If you have inotify in your kernel, check out inotify-tools.

There's an example on that page:

#!/bin/sh
# A slightly complex but actually useful example
inotifywait -mrq --timefmt '%d/%m/%y %H:%M' --format '%T %f' \
 -e close_write /home/billy | while read date time file; do
    rsync /home/billy/${file} rsync://billy@example.com/backup/${file} && \
    echo "At ${time} on ${date}, file ${file} was backed up via rsync"
done

Answer 2

use the inotify system of linux, in combination with incron.