Can I format HDs and SSDs with APFS running El Capitan?

[FMiguelez]

I've been doing some reading about APFS, and it seems like a very good and better file system than we've had up to now.

I wonder if I can use that format in my HDs and SSDs with my Macs running El Capitan?
One of them (the office one) won't allow me to instal anything higher than El Capitan... It's old, but still good enough for office duties. The other ones can run Mojave, but at this point I'm only interested in APFS, not the rest of the OS.

The only thing that disappoints me about APFS is that, despite its new features, it seems it does not do much for data integrity, i.e., bit rot

That's not particularly good... and I didn't get the feeling Apple will address that anytime soon. Hopefully I'm wrong about that!

[bayswater]

it seems it does not do much for data integrity, i.e., bit rot

That only happens in hot climates

There was a workaround from Paragon that let you use APFS in earlier OS versions, but it was discontinued in August. If you google apfs in El cap you'll see a few others, but they all looked dodgy to me.

[mikehalloran]

The only thing that disappoints me about APFS is that, despite its new features, it seems it does not do much for data integrity,

How so?

APFS means strong encryption: The other big advantage to APFS is that it’s designed with encryption in mind. It combines the full disk encryption features found in the latest versions of OS X with the data protection feature that encrypts every file individually on iOS.

This fits Apple’s focus on privacy and security perfectly. When APFS is made available, you’ll have three options to choose from on macOS: no encryption, single-key encryption and multi-key encryption with per-file keys for file data and a separate key for sensitive metadata.

[bayswater]

The only thing that disappoints me about APFS is that, despite its new features, it seems it does not do much for data integrity,

How so?

APFS means strong encryption: The other big advantage to APFS is that it’s designed with encryption in mind. It combines the full disk encryption features found in the latest versions of OS X with the data protection feature that encrypts every file individually on iOS.

This fits Apple’s focus on privacy and security perfectly. When APFS is made available, you’ll have three options to choose from on macOS: no encryption, single-key encryption and multi-key encryption with per-file keys for file data and a separate key for sensitive metadata.

I think the reference is to whether your data lasts, not whether it can be hacked.

[FMiguelez]

Exactly!

I saw numerous references for security/privacy, which seems excellent, but nothing compelling about data integrity.
Bit rot is just one issue, but I understand that, since the data in the SSD is constantly being rewritten and shuffled around, there should be redundant mechanisms to check the data constantly.
From what I've read, and I'm happy to be corrected, is that APFS doesn't do much checksums to prevent this. Not that it's bad, but could be much better...

https://arstechnica.com/gadgets/2016/06 ... -system/3/

Also, it may be I'm not understanding the full picture correctly

[FMiguelez]

There was a workaround from Paragon that let you use APFS in earlier OS versions, but it was discontinued in August. If you google apfs in El cap you'll see a few others, but they all looked dodgy to me.

Ha!
You're right! I just checked and I didn't find anything that filled me with confidence about hacks for my precious files! No way!

[bayswater]

Exactly!

I saw numerous references for security/privacy, which seems excellent, but nothing compelling about data integrity.
Bit rot is just one issue, but I understand that, since the data in the SSD is constantly being rewritten and shuffled around, there should be redundant mechanisms to check the data constantly.
From what I've read, and I'm happy to be corrected, is that APFS doesn't do much checksums to prevent this. Not that it's bad, but could be much better...

https://arstechnica.com/gadgets/2016/06 ... -system/3/

Also, it may be I'm not understanding the full picture correctly

On checksums, the article you cited says:

" Both NAND flash SSDs and magnetic media HDDs use redundant data to detect and correct errors. The Apple engineers contend that Apple devices basically don't return bogus data. NAND uses extra data, e.g. 128 bytes per 4KB page, so that errors can be corrected and detected. " There are checksums for the metadata, so at lease the way the OS sees your data is monitored by that. Somewhere else, they suggest that modern devices are good enough that they can be expected to return zero errors over their useful life. If so, could we be at the point where the checksum process is more likely to return an error than bad data?

The bit about the way copies are handled emphasizes the need to do backups.

[mikehalloran]

If that article was based on the Apple white paper (that doesn’t exist) and wasn’t written a year before the release of High Sierra, I’d give it some credibility instead of dismissing it as armchair speculation.

The bit about the way copies are handled emphasizes the need to do backups.

Since we don’t really know what’s going on—and neither does the author, that’s the safest attitude to have.