Backing up a PR4100

I have a PR4100 that I use for storing all my media on. I also use Acronis True Image to backup my entire PC onto the PR4100.Then I have Elephant Drive as cloud storage for the media files on the NAS.
I am thinking about adding another layer of backup to the system.
Could I add another cheap NAS to my network and then automatically copy files from my PR4100 to it, maybe using Goodsync or something?
Could I use a cheap WD My Cloud Home unit for instance?

connect a WD mybook to the usb port on the nas ( there are 2 ports in the back )

then use the NAS to USB app to back up ( need to download it as it is no longer included)

if you leave the USB disk connected you can view and access on line or disconnect and store off-line

I use two 4GB mybooks as my raid 1 nas has 8 GB of data on 2 shares.

Hi, I have one of these and have been using the onboard uSB app to make backup job, but it does not have a scheduler so I usually forget.

yes - a manual action is needed

and the USB backup app is updated

but the Sync task on os5 is working a bit strange on large Acronis backup files.

on a second run it was doing a replacement of large files that had not changed ?