Originally Posted by rjo98
Guess I'm still not not understanding how/when you should use primary vs. non-primary, and doing some reading looks like you can/should mark one partition as "active" somehow too?
"active" is also a non Linux (at least non Grub) concept.
I'm pretty sure Centos still uses some form of the Grub boot loader and very sure it still uses some boot loader that doesn't care about primary vs. logical and doesn't care about active.
A Windows boot loader needs to load part of itself from a primary partition. Windows compatible MBR code loads that part of the boot loader from the "active" primary partition. Windows then expects that its boot code was loaded from the active partition. Various multi-boot systems (including Grub) have ways of patching which partition is "active" at boot time in case you have more than one version of Windows or other non Linux OS that cares about "active". But all that only matters if you are multi-booting multiple OS's and some of them are not Linux (it only is complicated enough to need your attention when more than one of the OS's is non Linux).
Linux doesn't care about any of that.