Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

SkyLinx

macrumors member
Original poster
Mar 24, 2018
51
11
Espoo, Finland
Yesterday night I enabled FileVault in my iMac (2017), and it's still encrypting. Earlier it said it would take more than one day to finish, now it's saying 15-16 hours. diskutil in the terminal says it's at 66%...

Questions:

- is it normal that it is taking this long with High Sierra also on a very recent Mac?
- the startup disk is a Fusion Drive. Does FileVault in HS affect in any way how Fusion Drive works / organises automatically data between the SSD and the hard drive?
- does the Core i5 in the iMac have hardware support for the encryption used by FileVault? if yes, does FileVault in High Sierra affect performance anyway once the initial encryption is complete or isn't it noticeable these days with latest OS and hardware?

Thanks!
 

Kingcr

macrumors member
Feb 1, 2018
86
75
UK
If you open activity monitor to show disk activity and leave it there without any keyboard or mouse activity, you may notice that the disk write activity drops off quite dramatically after exactly 5 minutes. If you’re experiencing this, you’ll either need to keep providing input every 5 minutes or use a mouse jiggler program to keep FV going at full speed.
 

ignatius345

macrumors 604
Aug 20, 2015
6,695
10,812
Whatever you do, do NOT right-click and choose "encrypt" on an external drive unless you want it reformatted to APFS. High Sierra will (without telling you) reformat it to APFS and therefore it will no longer be Time Machine compatible. I know you didn't ask about this, but I got bit by this bug recently and nuked many months of backups.

more here:

https://bombich.com/blog/2017/09/29/think-twice-before-encrypting-your-hfs-volumes-on-high-sierra

https://www.macworld.com/article/32...hine-drive-using-apfs-and-thats-not-good.html
 
Last edited:

Kingcr

macrumors member
Feb 1, 2018
86
75
UK
Whatever you do, do NOT right-click and choose "encrypt" on an external drive unless you want it reformatted to APFS. High Sierra will (without telling you) reformat it to APFS and therefore it will no longer be Time Machine compatible. I know you didn't ask about this, but I got bit by this bug recently and nuked many months of backups.

more here:

https://bombich.com/blog/2017/09/29/think-twice-before-encrypting-your-hfs-volumes-on-high-sierra

https://www.macworld.com/article/32...hine-drive-using-apfs-and-thats-not-good.html

OP already mentioned he has a fusion drive so this does not apply here.
 

SkyLinx

macrumors member
Original poster
Mar 24, 2018
51
11
Espoo, Finland
If you open activity monitor to show disk activity and leave it there without any keyboard or mouse activity, you may notice that the disk write activity drops off quite dramatically after exactly 5 minutes. If you’re experiencing this, you’ll either need to keep providing input every 5 minutes or use a mouse jiggler program to keep FV going at full speed.

Uhm not sure I see any particular difference. Why would it be slower in idle? Shouldn't it be the opposite?

Whatever you do, do NOT right-click and choose "encrypt" on an external drive unless you want it reformatted to APFS. High Sierra will (without telling you) reformat it to APFS and therefore it will no longer be Time Machine compatible. I know you didn't ask about this, but I got bit by this bug recently and nuked many months of backups.

more here:

https://bombich.com/blog/2017/09/29/think-twice-before-encrypting-your-hfs-volumes-on-high-sierra

https://www.macworld.com/article/32...hine-drive-using-apfs-and-thats-not-good.html

Oh OK. Note taken. At the moment my Time Machine USB drive is formatted as HFS+ and TM backups are not encrypted. If I enable "Encrypt backups" in the TM options will this also convert the drive to APFS? Or will just do encryption at file level rather than at file system level?
 
  • Like
Reactions: ignatius345

donawalt

Contributor
Sep 10, 2015
1,102
533
Whatever you do, do NOT right-click and choose "encrypt" on an external drive unless you want it reformatted to APFS. High Sierra will (without telling you) reformat it to APFS and therefore it will no longer be Time Machine compatible. I know you didn't ask about this, but I got bit by this bug recently and nuked many months of backups.

more here:

https://bombich.com/blog/2017/09/29/think-twice-before-encrypting-your-hfs-volumes-on-high-sierra

https://www.macworld.com/article/32...hine-drive-using-apfs-and-thats-not-good.html

Given this I wish I could remember how I encrypted my Time Machine backup, as it's been awhile. But I am on High Sierra 10.13.4, and my encrypted non-APFS drive works fine on Time Machine:

Screen Shot 2018-04-13 at 3.43.08 PM.png
 

ignatius345

macrumors 604
Aug 20, 2015
6,695
10,812
Given this I wish I could remember how I encrypted my Time Machine backup, as it's been awhile. But I am on High Sierra 10.13.4, and my encrypted non-APFS drive works fine on Time Machine:

View attachment 758173
Yeah, encrypted is fine for Time Machine, but APFS is not. I'm assuming you must have encrypted it either using another method and/or before High Sierra.

I'm not 100% sure exactly which methods trigger the silent APFS reformat, but I know right-clicking the drive itself sure does because I hosed my own drive that way :/
 
Last edited:

ignatius345

macrumors 604
Aug 20, 2015
6,695
10,812
OP already mentioned he has a fusion drive so this does not apply here.

Yeah, obviously it doesn't apply to Fusion drives, but it is relevant to the subject of drive encryption under High Sierra.

I also wrote "I know you didn't ask about this" indicating that it was just a friendly heads-up... so maybe chill?
 
Last edited:

SkyLinx

macrumors member
Original poster
Mar 24, 2018
51
11
Espoo, Finland
You’d think so, but this started happening for some of us from Sierra onwards.

https://discussions.apple.com/thread/7908056

Do you know what? I have been watching the progress and I can actually confirm that while I use the iMac FV encryption is indeed faster! For example from 10 am until 4.30 pm it had progressed only by a ridiculous 1% to 84%, then I started to use the computer and now, less than half an hour later, it jumped to 87% already, so it's indeed progressing more quickly at the moment. Sys Prefs now estimates "2 hours remaining" instead of "more than one day" (I know that estimation isn't accurate at all but still...)

This must definitely be some sort of bug because it should be the opposite. Uhm
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.