I have several terabytes of data I need to back up to S3/Glacier over a slow link. I want to upload from, say 9pm to 9am and resume from where it left off. Is there free software that would do that easily? I could use s3cmd/s3sync for the uploading, but is there a simple way to control it with cron? I'm OK with several days latency, since I have static data and am just adding another layer of redundancy.
Would it be best to just start a process and kill it, then restart sync? I'm mainly looking for a standard system, but I could probably just write some shell scripts. I'm using Ubuntu and want to use standard Linux tools.