acessing 3 USB HDDs

[mpif90]

Hi,
I have 3 USB HDD's 2x2TB + 1x750GB. All are different Western Digitals. Two of them already have data. I would like to have 24/7 access to the data over the network. What options do I have?

I am thinking of building a NAS and using those disks as usb attachments. BTW most disks are 2-4 years old. Any issues there?

 

[dayana]

You may have the secondly mirror the first, and then third mirror the second, then if first one failed, switch the access to second one, if second one failed, switch to third.