APFS up close: What Mac users need to know about Apple's new file system


Last week’s worldwide builders convention in San Jose included an replace on Apple’s new APFS file system. Here are the important thing takeaways for customers.

APFS is operating on lots of of tens of millions of iOS gadgets as we speak. Apple examined the iOS conversion utility in iOS 10.Zero-2, doing a “dry run” throughout installs, to search out and repair issues. As a outcome, the iOS conversion to APFS has been very clean.


For macOS, High Sierra robotically converts the system drive to APFS as a part of the set up course of. The course of doesn’t transfer your file knowledge. It does copy and reformat file system metadata, however doesn’t erase the previous metadata till the rewritten metadata has checked out.

If you have got a couple of drive nevertheless, different drives have to be upgraded manually, through Disk Utility. Select the amount to be upgraded, left click on, and the contextual menu has a Convert to APFS choice.

If you might be utilizing FileVault, which I like to recommend, macOS will automagically convert it to APFS with out decrypting your knowledge. Your passwords and restoration keys are preserved within the course of.


When a clone is created, solely metadata is copied, which signifies that even very massive information clone virtually immediately. When the file is modified solely the modified blocks are written to free house.


Snapshots are much like clones, in that they protect the state of the file system at a selected second. APFS remembers all of the references and metadata and, utilizing Copy On Write (COW), solely writes newly modified blocks after the snapshot. Snapshots use some capability, however a lot lower than a whole copy would.


APFS affords deep assist for encryption on the file and quantity degree. Cool characteristic: If you snapshot an unencrypted drive, and later encrypt it, the snapshot is encrypted as properly.

Fusion drives

APFS will hold metadata on the SSD portion of the fusion drive, as properly a write again cache and a learn cache. This ought to make listing lookups actually quick.

Time Machine

Not solely is Time Machine supported underneath APFS, it’s a lot improved. I finished utilizing Time Machine years in the past as a result of it slowed my machines down a lot. But with APFS’s snapshot functionality, the TM software program is way less complicated and approach sooner.

One cool new characteristic: The previous Time Machine could not again up information bigger than about 20MB. With APFS there is not any restrict.

Intelligent defrag

SSDs do not want defragmentation, however arduous drives do. APFS understands which information will give the most important efficiency increase as soon as defragged. It works within the background when the machine is idle, so defrag will not impression system efficiency.

The Storage Bits take

Although APFS would not examine each 21st century characteristic field, it’s nonetheless an enormous and lengthy overdue improve from HFS+. I am cautiously optimistic that the conversion will go properly.

Of the brand new particulars from the WWDC speak, I am most happy by the promise of a vastly improved Time Machine. Perhaps it should lastly be the backup utility that I’ve needed all alongside. While I’ve lengthy used Superduper! and Carbon Copy Cloner, I might quite that performance be constructed into macOS.

But the promise of upper efficiency and higher knowledge integrity is sufficient for me. Let’s hope builders give you inventive methods to make use of these new options.

Courteous feedback welcome, after all. For extra element on APFS options and what they imply, examine this out.

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