Recover data from old drives. (Nothing sees disks?)

[bakes82]

I have 8-10 4tb unraid drives that use to work as of 1-2 weeks ago.  The server then started throwing memory issues and I cant seem to get it to boot any more.  So I bought a NAS instead and was looking to get a few files off the old drives.  It doesnt seem like anything I use can see the files.  I put the old drives in the NAS and was just going to format some of my smaller ones that were like 1tb and 3tb that I used for download storage, but the NAS cant even see the disks.  Using a usb and Ubuntu it couldnt see the 4tb disks (might be driver realted), but the usb toaster thing cant see the 1tb drive either which is odd.