Mac OS Extended for HD and APFS for SSDs - Still good advice?

[Sawday]

When I acquired my 'new to me' iMac I formatted my external hard drives to APFS but left my TM disk as Mac OS Extended (Journaled). My external disk are getting slower and slower to wake and I'm now wondering is this formatting is to blame. Should I revert to using MacOS Extended for my external drives and leave APFS solely for my internal SSD?

 

[Rod]

All "new" macOS require APFS and although Mac OS Extended (Journaled) will still work on a HDD for TM it is not the recommended format.

"
APFS (Apple File System) is the preferred format for Time Machine backups, especially on macOS 10.13 or later. It offers several advantages such as full-disk encryption, the ability to create point-in-time snapshots, and cloning of files. However, APFS does not support compression, Fusion drives, and encrypted volumes are not easily accessible.

HFS+ (Hierarchical File System Plus), also known as Mac OS Extended, is compatible with all versions of macOS and Mac OS X. It supports Fusion drives and encrypted volumes are easily accessible. However, HFS+ does not support snapshots and lacks native file support and data integrity checksums.

For an external HDD used exclusively for Time Machine backups, APFS is generally recommended due to its advanced features and future compatibility. However, some users report that APFS may perform less efficiently on HDDs compared to SSDs, potentially leading to slower performance over time."

So, regarding that last paragraph, the simple answer is to use an SSD for your TM backup but, I'm using a HDD for my TM backup, formatted as APFS and have not encountered any problems.

 

[MacInWin]

In addition to Rod's excellent summary, the decision of APFS vs. HFS+ should not be based in internal vs. external, but rotating vs. solid state.

APFS is specifically optimized for SSDs and may create really bad fragmentation on rotating drives. Actually, the fragmentation is in both types, but is pretty meaningless in SSD, but seriously impacts rotating drives.

As for TM, in modern versions of macOS it will force APFS on the backup drive, whether rotating or solid state, and also force Case Sensitive and Encrypted as well. Now, normally TM backups don't see a lot of activity that would cause fragmentation and slowdown, so I don't think it's as critical as for a "working" drive that gets more activity in file writes and/or edits. And that may well be why Rod hasn't encountered any problems with it (and is unlikely to do so in the future).

 

[RadDave]

When I acquired my 'new to me' iMac I formatted my external hard drives to APFS but left my TM disk as Mac OS Extended (Journaled). My external disk are getting slower and slower to wake and I'm now wondering is this formatting is to blame. Should I revert to using MacOS Extended for my external drives and leave APFS solely for my internal SSD?

Hi Sawday - you've already received great advice from Rod & Jake - recently I upgraded my computers to iMac (M3) and laptop (M2 Air) and decided to redo my TM backups using APFS (case sensitive) on new SSDs, seemed like a good move, especially after just reading the article by Howard Oakley HERE recommended by Jake recently - of course your choice, but SSDs and the APFS are likely in your future. Dave

 

[Rod]

Yeah, I wont be buying any more HDD EHD's, I'm only using this Transcend 1TB drive because it refuses to die.

 

[Sawday]

Just to be clear, my external drives incl TM drive are all HDDs. Only the internal drive is an SSD.

 

[Rod]

I get that Sawday, and for as long as they may last I'd stick with them but APFS is the way to go for TM backups on anything.

 

[Sawday]

Thanks everyone.