We have a NAS in our data center that we use for backups and application data. It has the ability to have an external USB hard drive connected to it and all data can be backed up to that drive.

Here is what I am trying to accomplish:

I want 2x RAID1 external enclosures, each with 2x2TB drives. As a backup procedure, I want to go to the data center and swap out one of the drives, and take it to the office, insert it into the second enclosure and have a mirror of the data...then repeat every 2 weeks. So we have a copy of the data locally. How can I make this happen? I want to make the process as automatic as possible.

Also, Are there any products that anyone can recommend that would allow for this?

EDIT: We have a 8 bay Synology Rackstation as our Production NAS. The external enclosure will attach to that. So no issues while external enclosure is being rebuilt.

  • For starters, the office enclosure is not going to sync the data on the swapped drive to the remaining drive, it's going to sync the data on the remaining drive to the swapped drive, thereby losing the data on the swapped drive. – joeqwerty Sep 5 '14 at 17:09

That doesn't sound like backup-- that sounds repeatedly damaging your fault tolerance and exposing yourself to risk while the production array rebuilds.

I couldn't consider this backup, either, because you're not creating multiple generations of copies and you're not storing those copies offline. (Backup means three things to me-- off-site, off-line, and multi-generational.)

I think you'd be better off using an actual backup tool. You don't mention your specific NAS model, but you could use any one of a number of tools to create backup sets that contained both full and differential backups that would allow you to recover multiple generations. (We don't recommend specific tools here-- there are certainly a number of products, both free/open source and proprietary in this space.)

Depending on the amount of data "churn" you may have enough bandwidth to perform the backups remotely.

Your NAS device may already have support for a protocol like rsync that would make this much easier, too.

If you're set on using hard disk drives as your backup "cartridges" you could easily end up with a situation where you have multiple disks that you rotate on / off the network to make multi-generational copies and to have an offline copy. (Offline is important. It's virtually impossible for a mistake or a malicious attack to destroy a copy of your data that's sitting in physically secure location disconnected from the network.)


Based on your comment you're just making copies of the production NAS onto a glorified external drive, then.

That seems reasonable from a "you're breaking your fault tolerance" perspective. I'd still want to have multiple generations and an offline backup.

I'd take that external drive back to the office and make generational backups against the office snapshot. Then I'd store the external drive offline.

Two weeks is a long recovery point objective, but if that's acceptable then so be it.

  • I should have been more clear. The hot swap device is not the production NAS. It is a separate 2 bay enclosure that plugs into the production NAS. THe production NAS is a synology 8 drive rackstation. Basically, I use the synology to backup to the external enclosure which I then use to swap the disks out of. Does that make sense? I have way too much data to rsync as we pay for bandwidth. – Chris Kooken Sep 5 '14 at 17:28

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