Is there any issue having an external HD with an HFS+ & APFS partition?

[logicstudiouser]

My plan is to format a 2TB drive in 2 partitions on Sierra with Mac OS Extended (Journaled).
1TB will be for a Mojave partition, which when installed, will convert (against my will ) to APFS.
The other 1TB will be a music backup, which will stay on HFS+.
Is there any problem with having both HFS+ and APFS on the same drive?

 

[treekram]

You can have both HFS+ and APFS on the same drive.

If you have a SSD, the installer will convert to APFS if necessary. For a HDD, it will not convert HFS+ to APFS.

For macOS, if you decide to delete a partition at a later date, you can resize the previous partition to take that space. The same is not true for the reverse.

If you have a SSD, you should consider APFS (add another volume, not another partition) for your music - it will automatically resize volumes (with certain caveats) so if at a later date you really need 1.1TB for music but only use 700GB for the OS, the OS automatically does that. Doing that with a mixed HFS+/APFS disk requires copying data off the 2nd partition, resizing the first partition and then copying data back to the 2nd partition. APFS seems to be mostly stable now, with the exception of fusion drives and certain older Mac Pro configurations.

 

[Fishrrman]

I've done this, and it seems to work ok.

That is:
1. Partition FIRST, using a Mac OS that is running under HFS+ (i.e., 2 HFS+ partitions).
2. Then install Mojave after that to one of the partitions.
3. The partition you install -to- will get converted to APFS.
4. The -other partition- should be "left alone" in HFS+

That worked for me.