Does APFS use more disk space compared to HFS+

[flackooo]

I've attached a screenshot below showing the exact same folder stored on 2 drives, one formatted to apfs and the other hfs+. The folders are both identical but on the apfs drive it's taking up considerably more space on the actual disk although the actual size of the folders are identical.

Can anyone explain the logic behind this to me? APFS drive is an SSD and the HFS drive is a HDD is that actually the main factory here and not the different file systems? Any input would be greatly appreciated, on a 1tb folder it seems to store a whole 13gb more on the APFS SSD than the HFS HDD which is huge

 

[treekram]

The difference in your screenshot is 0.28 percent for the 116 GB in the example you provide. You don't provide details so I'm going to make some assumptions.

Assumption: 1TB is the size of the SSD (vs. the size of a folder on the SSD) and the 1TB SSD is your system (boot) disk when the screenshots were taken. If these assumptions are true, then there will be files on a system disk not on a non-system disk. If you're doing some sort of cloning operation, unless you do a byte-by-byte exact copy (usually done when the disks are not active), most typically used cloning methods will avoid copying some files because these files only makes sense at the time the computer is being run on the computer it's being run on. You also have volumes in APFS that are not present on HFS+, most notably, space-wise, is the VM (virtual memory) volume which on my computers that have High Sierra on them, is 2GB, that may vary - I don't know the particulars of whether or not Apple varies the size of this volume based on SSD and RAM size. Even if you weren't using virtual memory at the time, in APFS, that space is reserved for the VM volume and thus will be seen as used by the OS by APFS. And there's the sleepimage file which likely isn't copied over and perhaps Time Machine local snapshots which may or may not be copied over.

To me, the 13GB size difference on a 1TB SSD isn't something to be worried about. But if you're interested in more details, enter "diskutil list" in the Terminal app and post them. Also check the size of the /private/var/vm/sleepimage files and post that (and see if it was copied to the HDD). If you use commercial software like CCC or SuperDuper, you can check with the vendors and see which files they don't copy over. Look up Time Machine local snapshots and if it's not important to you, delete them and see if that makes a difference. Even if Time Machine is disabled, there may be a local snapshot taking space.

 

[flackooo]

Hi thanks for your reply but none of the things you mentioned are determining factors, the SSD is 2tb as is the HDD, the drives are both external (although the same added space on disk also applies to my internal APFS SSD). There is no cloning and I'm not using Time Machine (and never have) or any third party tools all my backing up is done manually copying the entirety of the disk to the backup I have disabled sleep image and the file is immutable 0 bytes, the only differing factors are the fact one is an SSD and one is a HDD and one is APFS and the other is HFS+

If anyone uses an APFS SSD (can be internal) and has a fairly large folder over 100GB such as their home folder and can let me know if this is normal and you're seeing the same sort of thing with a significant amount being stored on the disk compared to the actual folder size even if it's just a few hundred megabytes that'd be greatly appreciated so I can rule it out being my configuration

 

[HDFan]

Yep, seeing same thing, but reversed:





It has been a while I looked into Unix filesystem structures, but there is a whole lot of information associated with a file. The associated blocks, the permissions, whether it is a link, directory, etc. Same thing for the directories and master disk directory. Since the two file systems are different they would differ in the metadata needed for filesystem operation.