Apple Event: May 7th at 7 am PT
How to convert EXTERNAL BOOTING SSD HFS+ with MacOS 10.12 Sierra to APFS-formatted with macOS 10.13 High Sierra? Is it recommended (pros and cons)? For instance, for Samsung Portable SSD T5. Thanks!
iMac with Retina 5K display, macOS Sierra (10.12.6), Booting from internal Apple SSD 2TB
"The only compelling reason to convert your external SSD is to satisfy your own curiosity".
Then, I understand that the external High Sierra booting SSD will not work better if formatted as APFS, and that there is no advantage of it over HFS+. But I also understand that for internal High Sierra booting SSD, it is better to format as APFS, and that is why Apple does that automatically without allowing users to do otherwise. Right?
But if that is so, my question is: what is the advantage of APFS for internal High Sierra booting SSD that do not have external ones?
John, thanks for the link. As you say, APFS has certain undeniable advantages ove HFS+. For instance:
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Crash Protection
Apple File System uses a novel copy-on-write metadata scheme to ensure that updates to the file system are crash protected, without the write-twice overhead of journaling.
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What I do not understand is why then you are not advising to format external booting SSD as APFS, since it has such advantages.
I didn't advise you either way. In fact I encouraged you to find out for yourself, as I did.
There is nothing wrong with journaling. APFS does the same thing more efficiently because it's inherent in its design. I have tried and failed to introduce corruption in a journaled HFS+ formatted volume. Although the APFS tests I conducted were not as extensive I have found it to be equally robust. If it's more efficient, so much the better.
Copying files (for example) is ridiculously fast, but it was fast enough under HFS+, especially with flash storage.
John said:
"Converting a Sierra boot volume to APFS and then installing HS is unconventional since the installer will expect to find a Sierra (or earlier) OS on an HFS+ formatted volume... not one already converted to APFS".
Yet, bbidvet said (as I did before):
"I believe I read that installing HS on an external SSD will not automatically make it APFS. You would need to format the SSD first as APFS and then install HS".
So, what is the current status using macOS 10.13.2? I know that I can "test", but I am asking in case someone knows. Pioneers get the arrows... Thanks.
You cannot convert APFS to HFS nor the reverse non-destructively? Apple High Sierra installer converts HFS+ into APFS (without asking or reporting) for all internal SSD booting disks, as far as I know.
In short, I have a Sierra external booting disk (Samsung Portable SSD T5) and want to upgrade to High Sierra with APFS. How to do it? I guess this:
1. Make backup of Sierra disk with Time Machine or SuperDuper.
2. Format disk as APFS.
3. Restore from Time Machine or SuperDuper.
Is that correct? Thanks.
Pretty close. You should make a bootable clone using SD! or Carbon Copy Cloner onto a disk formatted using HFS+ then restore it. Or make a bootable clone of a disk already formatted using APFS to a disk formatted with APFS.
Thanks. When you said
1. "You should make a bootable clone using SD! or Carbon Copy Cloner onto a disk formatted using HFS+ then restore it", I understand that you meant:
You should make a bootable clone of Sierra external booting disk (Samsung Portable SSD T5) using SD! or Carbon Copy Cloner onto a disk formatted using HFS+. Then format the original T5 as APFS (all data will be lost) and then restore it from the backup. Right?
2. "Or make a bootable clone of a disk already formatted using APFS to a disk formatted with APFS", I understand that you meant:
Or format a brand new T5 as APFS, install High Sierra into it, and then use Migration Assistant to import all contents of original Sierra external booting disk (Samsung Portable SSD T5). All contents will be imported except macOS itsef, since High Sierra is newer than Sierra. Right?
If both methods are correct, which one would you recommend. Which one would be better (more reliable, fast, etc). Thanks for all your kind support.
The last paraghraph should read (this forum does not allow to edit and even gives wrong messages like try later!):
If both methods are correct, which one would you recommend? Which one would be better (more reliable, faster, etc). Thanks for all your kind support.
In short, I have a Sierra external booting disk (Samsung Portable SSD T5) and want to upgrade to High Sierra with APFS. How to do it? I guess this:
Perhaps the order of operations is wrong.
You might try upgrading to High Sierra, then converting the drive to APFS. It may be that Disk Utility knows that Sierra cannot boot APFS and is not allowing the conversion. If it has High Sierra, perhaps it will then allow you to convert. I don't have an external SSD to try.
According to some documents I found online any external drive that is a clone (bootable) cannot be converted to APFS using Disk Utilities. You must format the external drive to APFS before cloning. I ran a test with a drive that was bootable and non bootable and that was the case.
You might try upgrading to High Sierra, then converting the drive to APFS.
It appears that may not be an option, either: Converting external SSD to APFS
He’s talking about an external SSD, not a mechanical HD.
You threw in the sentence, “It is not recommended for HDDs or Fusion Drives. ”
My mistake then, sorry.
Quite right, Lanny. Only High Sierra fully supports APFS on SSDs.
No sweat. At least you are polite about it. That's appreciated.
How to convert EXTERNAL BOOTING SSD HFS+ with MacOS 10.12 Sierra to APFS-formatted with macOS 10.13 High Sierra?
