I am a computational biologist working for a small startup tasked with setting up a local implementation of a small tower server (if it matters, I'm looking into getting a PowerEdge T620 or similar) for use as a compute system & small MySQL implementation.

My concerns lay in data security, more specifically, how I handle data backup. We would like flexibility when it comes to overall storage, however our starting point for storage is at the 6TB mark. Therefore, I'm envisioning the use of 2 x 3TB drives.

I'd like to have a strategy in which I always have a backup copy of my data (updated every evening) accessible to the server & an off-site copy (which is physically brought in and updated over the weekend).

It looks like the server has several RAID options (through their PERC H310 Integrated RAID Controller), three that seem particularly useful in my case are 

* RAID 10
* RAID 0+RAID 0
* RAID 1+RAID 10

My question: is it safe/advisable to swap out the two hard drives that make up the backup copy for the two that make up the off-site copy, and do that backing-up that way?

Or should I look into buying a RAID enclosure which will act as the off-site backup and connect it through something like USB3.0?

Note: I'd like to physically disconnect (at the least power down) the backup while updating the off-site (that is, I never want all drives attached to the server). Therefore, I'm wondering how feasible it is to pull drives out and swap them with others.

Secondary question: Dell's RAID 0+RAID 0 setup is described like this - 

> 
> RAID 0+RAID 0 for H710P/H710/H310 (1 SATA + 1-31 SAS HDDs) add $0.00
> 
> 
> 

Is it even possible to use four drives split into two RAID 0 setups?