I recently bought a 12 TB external HDD to replace an ageing and free-space-volatilising 6 TB hard drive. This external HDD is meant for user data only, though I might shift data to and fro other external HDDs as I see need. This external drive is a true extension to the internal SSD user document space, which is limited in size, so will be frequently accessed and updated. The 6 TB HDD is HFS+ formatted from a time when APFS wasn't an option for me. With the new HDD waiting, I wonder whether I should be formatting it as HFS+ or APFS.

I've read the advantages and disadvantages about APFS in this answer and based on that, I tend to want to format it as APFS, but I've also read in this article that mechanical disks run better with HFS+ due to its handling of fragmentation in the file system metadata. This is a concern shared in a question here, which @bmike refuted two years ago by suggesting to simply erase a heavily fragmented APFS disk and restore the data/install, something that I'm honestly not too keen on.

In addition, since that (first) linked answer is already 5.5 years old, I wonder if anyone has gained knowledge / experience in those years about the suitability of either file system in the long run for keeping user data.

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    @Allan I assume they're referring to the fact that APFS has undergone changes, not HFS+
    – Ezekiel
    Commented Mar 8, 2023 at 3:59
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    @Allan Not referring to any fact that APFS has undergone changes. I don't even know if that is a fact. No, I was referring to users having gained more experience with the suitability of APFS as file system on an external mechanical drive. That is the reference to age. — I have also not alluded to any assumption that a changing or developed APFS would make a deprecated FS a better choice. Commented Mar 9, 2023 at 0:39
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    @Ezekiel Correct, that was my thought, namely that the linked answers seem to suggest that HFS+ is a better choice for mechanical drives (unless specific APFS features are required), while in the time since those drawbacks might've lessened. I was after an answer like that, which would show either "yes, APFS is the way forward and those drawbacks are of no concern given enough users experiencing APFS on mechanical drives", or "no, APFS is still not suitable for reasons X, Y and Z on mechanical drives". I'm after practical user experiences. Commented Mar 9, 2023 at 0:43
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    I find it at times a bit intimidating to engage and participate meaningfully in discussions on Ask Differently when questions are closed so rapidly without given a chance to respond and clarify prior to closing. The other day a question of mine seemed haphazardly closed just because the mod didn't read the question right. I understand mods want to keep the quality of the forum up, but it's not always helping. – First associated Q above is relevant, but not identical, second Q isn't. Commented Mar 9, 2023 at 1:56
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    @Allan Well, one could argue that since the introduction of APFS, more users would've converted their external HDDs to APFS and therefore a greater collective knowledge about its suitability would exist in the community. As a technology gains maturity, so does the experience with it. What the linked Q&A doesn't answer is the impact of fragmentation, something which I specifically mentioned. Commented Mar 9, 2023 at 2:04


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