Backing Up 2 USB Drives Attached to Sinology DS2215

I have 2 [two] 4TB USB Eternal drives [LaCie] attached to my Synology DS215.
One of the external USB drive has data on it, which I would like to sync/copy to the other attached External USB drive.
Has anyone got any ideas/solutions as to how I can achieve this.
Thank you.

Are you doing a one-time copy, or sync, or both? Does the “/” mean “and” or “or”?

Hello rms,
ideally it will be first to copy all the data from one USB drive to the empty one, then moving forward perform sync either way

A bit off topic as this not much to do with macOS.

To copy files on the NAS, use Synology’s “File Station” app, or at the command line use “cp”

To sync files between two connected USB drives, I can’t think of any app Synology provides to do that local sync. You could use the command line program “rsync” which can not only do the initial copy but to the sync. You could set your batch file and then schedule with “Task Manager” in the “Control Panel”. Lots of articles on the Internet about how to use rsync with examples. The “man” file for rsync is good, and Synology has a user forum.

Using your mac connected to the NAS, you could use Finder to copy the files. To sync (which could include the initial copy, you could use Chronosync, Carbon Copy Cloner, or others. Further, you can run “rsync” on your Mac… I do that. I can’t remember if rsync is installed by macOS or I installed it myself from the freely available download site. Same as Synology, you could schedule the rsync to run with “cron”.

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To follow up on the previous post, here are the instructions for setting up a scheduled rsync between two folders on the same NAS (which should work with external drives/volumes as well) using Task Scheduler:

I’d also add that if this is your backup strategy, then please reconsider the approach. Folders will be kept in sync, including deleting files on either drive when they are deleted on the other. There’s no safety net here whatsoever.

Typically, for these sorts of tasks, including a one-way copy, you’d use HyperBackup on a Synology NAS, but I don’t think it will work with two external drives (it would, however, work for a backup of an internal volume to an external drive, with the added benefit that it can be configured to keep multiple past versions of a file although it will then use its own backup format and not a direct 1:1 copy).


What is it you are trying to achieve? What are you backing up? Backup of a backup created by Synology’s Hyperbackup?