Time Machine APFS - Multiple Drive Failures?

APFS was designed for SSD. Modern disk controllers handle it better than older ones (unless there was a firmware update for the drives - which only a few manufacturers ever do as far as I can tell, and even then mainly for their premium drives).

You have 10-year+ old HDD. The annualized failure rate of HDD increases with age (https://arstechnica.com/gadgets/2023/02/new-data-illustrates-times-effect-on-hard-drive-failure-rates/) and then also tends to spike in the 10-15 range (if a drive makes it that long).

Maybe APFS did reduce the lifespan of your HDD - but not by that much, I suspect. If you are going to replace them, complete solutions like a WD My Passport (or similar Toshiba, Seagate or Samsung offerings if you prefer those brands) will have modern disk control firmware designed for the drives in the device. If you are using an external enclosure, you should look for a reputable brand (and if using an enclosure now that is also a decade old, maybe replace it) and consider NAS class drives that are designed for the usage patterns associated with heavier read/write use.

I never did understand why Apple used WD Green drives in their Time Capsules - low power, sure, but their AFR was terrible.

Your previous posts sounded like you had older drives, up to 10+ years and 2-3 of them failed over a 2-3 year period. Maybe I misunderstood, but I don't think it substantively changes anything.

APFS is a very different filesystem from HFS+. Snapshots and delta extents for tracking changes across file clones, inode metadata stored with the files instead in a fixed location like in HFS+...you also don't say what version of macOS you are using and Apple has made changes to APFS over time - it could not originally be used for Time Machine backups and there have been improvements since that support was added in Big Sur.

Again, though, all these differences from HFS+ also results in very different write and read patterns than HFS+, and much more fragmentation and disk seeks on HDD - which don't matter on SSD because all seeks are logical address maps and don't involve any physical armatures.

I would expect any underlying issues of any HDD that would lead to disk failure to be accelerated if APFS is the filesystem, where it would not be if using HFS+, just because of the fragmentation issue alone.

SU wrote:

Big Sur might have had APFS support but not for time machine.

Is that so?

None of my Time Machine hard disk drives have experienced a single failure. I have over two dozen, all in daily service, with a number of different macOS versions including Big Sur. Some are "laptop" drives, some are "desktop" drives, and none are are SSDs. Some are over fifteen years old. All are using APFS, with the exception of Time Capsules or the hard disks connected to them. I have not experienced a single failure to back up or restore. Not one, ever.

Something else is going on. You appear to be fixated on APFS. Whatever the problem is, it's not that.

EtreCheck may provide a clue. Instructions: How to use the Add Text Feature When Posting Large Amounts of Text, i.e. an Etrecheck Report - Apple Community

<< I would consider that but prior to AFPS introduction there was no issues with drive failure. >>

your drives were newer then.

<< Then in a period of 2-3 yrs 3 drives failed on 3 different computers. >>

that as long as most rotating magnetic drives last, over VERY large samples. You do not have a VERY large sample, you have a handful of drives, and they are old.

SU wrote:

apple support. as they are not able to mount the drive and concluded the same conclusion .. a loss.

'disk won't mount' may simply be a corrupted directory.

can the disk be repaired with Disk Utility?

it may just need to be erased and start your anew, not necessarily failed drive.

<< anyone else having this issue? >.

Yes, EVERYONE else is having this EXACT issue.

What you are describing is the perfectly ordinary decay of drive's ability to hold data after it has been used for a long time. It is NOT specific got time machine, and your have NOT found any smoking guns. The only thing the slightest bit remarkable is that you are experiencing it at the same time on multiple drives.

[in my opinion] the only thing that really appears to be 'destroying' your drives is the normal aging process of drives.

What do you mean, EXACTLY, who you say drives have FAILED?