My understanding is MBR cannot partition greater than 2tb
No, MBR (and, by coincidence, FAT32) are limited to 4 terasectors (which, with most drives having half-kB sectors, equals 2 TB -- but "most drives" doesn't mean "all": "Advanced Format 4KN" drives, for example, have 4 kB sectors)
There's also no technical reason for the HBC, forwarders, usb loaders, ... not to support GPT - but it simply didn't matter to most people back then, and neither it does today, especially given how complicated recompiling an old homebrew may turn out to be
I question now is do I need to set both of them has PRIMARY?
Also, which one should I set as ACTIVE?
....Or does none of this really matter?
Being primary or logical isn't really an "option" of a partition, it's just the way it is:
- The (standard) MBR has room for 4 partitions
- At the time, given the size of affordable HDDs but especially limitations into early versions of DOS - you could only have 1 primary and 1 extended partition, and even later versions strongly discouraged multiple primary ones - 4 was more than enough
- The standard PC bootloader (which reads the partition table, then boots the active partition) doesn't directly support extended/logical partitions
So the MBR can hold at most 4 partitions: 4 primaries, or 3 primaries and 1 extended
(note that some disk management software hides the concept of extended partitions, handles them automatically, and only gives you the choice of primary or logical)
- A primary partition is one listed directly in the MBR
- An extended partition may be seen as a virtual disk with its own "MBR" (actually called "EBR"), but the EBR - while having the same structure of a MBR - is not used in the exact same way
- An EBR should have one or at most two partitions: 1 is a logical partition, 2 (if existant) is another extended partition, containing the next logical partition
Finally, as said above, an active partition is the one that will be loaded by the standard, noninteractive, PC bootloader - I doubt modern OSes (and their bootloaders) care, especially given you won't be booting from that disk anyway; the Wii as a whole certainly doesn't care and probably so do most homebrews; just note that not more than 1 partition must be active, to conform to standards
- MBRs support up to 4 terasectors for both "start position" and "size from there" figures, so MBR can actually address almost 4 TB (on a 512 B-sector drive) as long as you use exactly 2 partitions, and they both start before 2 TB
- The same is true of EBRs, so you could get a potentially infinite amount of partitions (each less than 2 TB) as long as all the ones after the 2 TB mark were logical
- Actual support for the 2 above tricks, as well as of the relatively new non-512B-sector disks, is questionable and may be limited by the software and operating systems involved (as well as by the USB-SATA converter you may be using, which shouldn't matter but sometimes does)
tl;dr make 2 primary partitions for now, then when you get tired of the hassle buy a <= 2 TB disk, or if you like to experiment with more games than you probably legally own, a <= 16 TB 4Kn disk