Using a Mechanical drive with the APFS file system may not be ideal - How to upgrade your iMac

[trs96]

I support many iMacs at work that are dated from about 2011 to 2013. They all came with either a 500 GB or 1TB mechanical HDD as the boot drive. It's always a good idea to upgrade them to Mojave (2012 or newer iMacs) and a new SSD. (opening one up is not a simple process though) The 2011s don't have Mojave support. We stop at High Sierra with those. All these models of iMac are already painfully slow when booting from the HDD and the conversion to APFS makes them even slower in my experience. I've always wondered how much slower they get after APFS conversion. I just saw this article on the CCC website by Mike. He has written an in depth analysis of why the new file system causes Macs with a HDD startup disk to get even slower. Very interesting read on this topic.

An analysis of APFS enumeration performance on rotational hard drives | Carbon Copy Cloner | Bombich Software

bombich.com

Mike says: The article is fairly technical, here are the key takeaways:

• Enumerating an APFS filesystem on a traditional HDD (rotational disk) will take 3-20X longer than HFS+ on the same hardware.
• This performance difference is most noticeable on a macOS startup disk that is (or includes) a rotational disk.
• If Apple doesn't make some concessions in the APFS filesystem to accommodate the slower seek performance of HDD devices, then a rotational device will never be able to provide acceptable performance as a production macOS startup disk.

My take home points for hackintoshers: Get an SSD to use as your boot drive if you want to run Mojave or Catalina. In 2019 no one should be booting from a mechanical HDD. If you do, expect to have painfully long boot times and lackluster performance once you reach the desktop. If you do buy an older refurb iMac you're going to need to learn how to open one up and install the SSD if you want it to be more than a museum piece. You can boot from an external SSD but then you've got desktop clutter that is the opposite of what the iMac does so well. It keeps your desk clutter and cable free.

This second video (Do It Yourself) gives you all the info on what you'll need for the SSD upgrade in a 27" iMac. OWC doesn't show that.

The downside of this DIY video is that he says nothing about electrostatic precautions. He's on carpeting when working on the SSD upgrade. Not a good idea. Note that the smaller 21.5" iMacs already use a 2.5" HDD so don't buy the third party SSD adapter as shown for the 27" model in the video. The suction cups are really helpful. If you were to drop the glass it can do some real damage. Just look at the LTT video on Youtube where they drop the glass on a brand new iMac.

Finally, here's a video by a technician that is in real time. He's upgrading the 21.5" iMac to a new SSD. This is a well done video that explains some of the risks of doing this procedure.

 

[Shiitaki]

I've replaced the mechanical drive in 5 Apple computers so far and the difference is staggering. The drives that come in Apple computers are not just slow because they are spinning rust, but special spinning rust modified to be the slowest drives you could possibly put in a computer. The transfer rate on the 3.5 from a mid 2011 iMac comes in around 65MB/s sustained, half the speed of some people's internet.

The cost of 50 bucks and your 8 year old computer suddenly is as fast a brand new iMac? Why would you not do that? The temperature sensor is a real in the iMacs, so there is that downside.

For most people swapping the mechanic drive in a mid 2011 iMac is just as good as a new computer. Obviously it won't install Mojave, but most people won't be bothered by that.

I like this "If Apple doesn't make some concessions in the APFS filesystem to accommodate the slower seek performance of HDD devices, then a rotational device will never be able to provide acceptable performance as a production macOS startup disk. "

Hello, mechanical drive, 2019, APFS is not the issue. If you care enough to want APFS then you care enough for an SSD. Otherwise, hfs+ is just fine.

I've had this discussion with people for several years now and they think I'm exaggerating. Then when they actually give in and go through the upgrade they are stunned how big the difference is.

 

[trs96]

I've had this discussion with people for several years now and they think I'm exaggerating. Then when they actually give in and go through the upgrade they are stunned how big the difference is.

It's the single most important upgrade to make for an iMac and a Mac mini when they've got a 5400 RPM HDD. Using APFS on a platter drive takes an already bad situation to a greater level of mediocrity. Don't know how Apple can still be selling some current iMacs with spinner drives or even the now outdated Fusion drives. They ditched the floppy disk drive, CD drive and VGA connectors way before everyone else did. It seems that they only kept the platter drives in iMacs because of the relatively high cost of 500-1000 GB SSDs. Putting those in would eat into their already high profit margins.

SSD prices have come down enough in the last few years that they should be using one in every 21.5" and 27" iMac. I certainly hope that the next iMac refresh completely eradicates the old school mechanical drives. We'll just have to wait and see.

I really don't agree with Mike's conclusion that you should change your backup drive to an SSD but it's still ok to use a platter drive with APFS as your boot drive. Here's what he says near the end:

If performance of your rescue backup is of paramount importance, then you should consider replacing your HDD backup disk with an SSD.

We offer some suggestions here.

Then he seems to condone using APFS on your internal platter/spinner boot drive:

Should I avoid using APFS on my HDDs?

No, let's not throw out the baby with the bath water. APFS has loads of really nice features, like snapshots and volume space sharing. Managing volumes within an APFS container is a dream compared to the older method of preallocating space to specific partitions. It's important to understand why we might expect to see performance differences between the two filesystems and when that might impact your use of the filesystem, but this one performance aspect on its own isn't enough reason to avoid it.

 

[trs96]

For most people swapping the mechanic drive in a mid 2011 iMac is just as good as a new computer. Obviously it won't install Mojave, but most people won't be bothered by that.

Do you install this $37.50 hard drive thermal sensor in the 27" 2011 iMacs or just skip that step ?
https://www.amazon.com/dp/B00J42AFUA/?tag=tonymacx86com-20

 

[UtterDisbelief]

Do you install this $37.50 hard drive thermal sensor in the 27" 2011 iMacs or just skip that step ?
https://www.amazon.com/dp/B00J42AFUA/?tag=tonymacx86com-20

Didn't know about that requirement to prevent fans going berserk (Not that I've ever upgraded a real Mac's HDD/SSD anyway). I get the impression it's only for a couple of iMac models?

 

[trs96]

I get the impression it's only for a couple of iMac models ?

Not sure how many of them have that. Looks as if none of the 21.5" iMacs need the sensor but all of the 2011 or newer 27" iMacs up to 2019 need it. iMacs have always been known to run hot due to limited airflow. That's why discrete graphics cards often have problems and die prematurely in them. You could look at the OWC videos to see that the newer 27" models still use those thermal sensors on the HDD. https://eshop.macsales.com/installvideos/ and then scroll down to see the specific iMac model year.

 

[maclinuxg4]

it importante taht all mecanics drive disk use HFS+, because mac os management will reduice the life of the use of those disks. So check all mecanic drive disk

 

[trs96]

it importante taht all mecanics drive disk use HFS+, because mac os management will reduice the life of the use of those disks. So check all mechanical drive disk

It appears that converting a 5 or 6 year old platter drive to APFS will contribute to HDDs wearing out faster due to the way data is scattered all over the disk. I'm not sure if SMART monitoring will help or not. What I use on Windows drives is the Crystal Disk Info app which will warn of imminent disk failure. Don't know of any equivalent software for macOS.

 

[trs96]

I've had this discussion with people for several years now and they think I'm exaggerating. Then when they actually give in and go through the upgrade they are stunned how big the difference is.

A quick and easy way to convert the "non-believers" is to boot from an external Mojave SSD via USB 3.0 or Thunderbolt on their iMac and show them just how much faster it can be.

Jaws will definitely drop.

How fast did that just boot up ?

 

[trs96]

Is there a way to turn off Spotlight Indexing ? Yes, there is. It's one small way you can minimize the wear and tear on a platter drive that has been converted to APFS. I don't know of any way to disable it on just the platter drive if you have both an SSD and platter drive in your build.

In Terminal

To Disable Indexing:

sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist

To Enable Indexing:

sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist