When to "APFS" and when not to?

[maccam]

Got a new iMac 24 and the internal drive came formatted APFS. My Time Machine drive I formatted "Mac OS extended journaled" but the computer changed it to APFS (case sensitive) on its own when I designated as a Time Machine drive.

I use Carbon Copy Cloner and somehow I formatted one of the data backup drives to APFS and one to Mac OS extended journaled. I wanted both CCC drives to be the same so I did a new backup but I formatted the drive I wanted to change as "APFS (case sensitive) and CCC did not like that and said something like your source drive and backup drive need to be formatted the same so I reformatted backup drive to APFS dropping the (case sensitive).

Since my new computer formatted the Time Machine drive to (case sensitive) on its own, why doesn't CCC like the combination?

When I received my new iMac I used Time Machine to transfer my things. It worked.

I have a full time data drive that is not a backup drive formatted "Mac OS extended journaled. Should I change this drive's formatting to APFS?

APFS use to be only for internal drives. So, I guess my question is "what the hell am I doing wrong as far as formatting external drives (both Time Machine, full time data drives, and backup drives?

Thank you

JAW

 

[JPAlbert]

Don't use "case sensitive".

For a data drive (no OS on it):
- If it's platter-based, I'd recommend HFS+ (Mac OS extended with journaling enabled, GUID partition format). APFS will overly fragment a platter-based drive, you may hear it "thrashing" quite a bit.
- if the data drive is an SSD, it can be either APFS or HFS+. I still like HFS+ because I can use the drive with other, possibly older Macs that may not be able to "recognize" an APFS drive...

 

[Tom_N]

The way that I understand it, APFS is more modern than HFS+ (in terms of its features) and is designed around SSDs.

HFS+ is a better choice for HDDs that you plan to use for general data storage. (I'm not sure what the recommendation is for Time Machine destination HDDs.) Reports say that APFS sometimes creates a fair amount of file fragmentation. Penalties for random access are much higher on HDDs than on SSDs – so something that's OK, or even an optimization, on a SSD, can hurt the performance of a HDD.