Seagate ST4000DX000-1C5160 [3726 GB] 4TB

cubewebsolutions - That is why the backup solutions are getting more and more difficult. You may want to think about your storage needs with the backups in mind. For many years I had only a single NV+ for my data, but as I added more and more (and the third drive and then the fourth) my previous backup plan which was not consistent became almost untenable. I was manually backing everything up to drives connected to my PC via eSATA. So I added an NVX in June of last year as my primary storage and the NV+ became by backup target. Later, when the prices dropped on the NVX (being discontinued) I added a second NVX for future growth. Each NVX now has 2x3TB and 2x1TB drives, with the second being the target of several rsync backup jobs every night. My backup is thus never more than 24 hours old. The rsync jobs only take minutes.

Unless you need 12TB of storage, you might want to consider two 4 bay units with one backing up the other. The backup target does not have to be as fast as the primary storage, for example you could go with a Pro4 or Ultra 4 Plus as the primary unit and an Ultra 4 as the secondary. The drive set could even then be moved intact from one to another since they are all x-86 system. If you had a problem you were not sure whether it was the chassis or the drives, you could shut down both, remove the drives from the one not having problems, move the drives from the one giving problems in the same order, and reboot. (If you have custom device names, that will go with the disk set. When I moved the drives from NAS1 to the brand new NVX BE, it came up as NAS1 and all my drive maps were intact).

When I upgraded two of my drives from 1TB to 3TB, I did the backup unit first and after a week, I did the primary unit. That gave me time to know there were not any problems with the drives and the backup was intact and stable. Unfortunately for our pocket books, once you reach a certain point in data volume, the only really efficient way to back up is NAS to NAS (IMO) unless you happen to have other large volume and fast backup devices laying around.