Defrag a MAC

I found this as well, https://www.macworld.co.uk/how-to/mac/defrag-3600241/

If you are from the future please refer the link to the waybackmachine at the internet archive

Mac do not need to be defragmented because the file system (initially HFS+ and more recently APFS) prevents fragmentation and automatically defrags files if necessary - if the file has more than eight fragments, or is smaller than 20MB, it will be automatically defragged.

HFS+, which was introduced in 1998, could defrag files on the fly thanks to Hot File Clustering. Then in Mac OS X 10.2, which arrived in 2002, the system got even cleverer at avoiding fragmentation. A year later, in 2003, Hot File Adaptive Clustering arrived, which identifies files that are frequently accessed but rarely updated and moves them to a special area of the drive, defragging them during the process.

Apple then introduced APFS (Apple File System) in High Sierra in 2017. APFS was initially only available on SSDs (which as we’ve already said, shouldn’t be defragged anyway), but it arrived on hard drives and Fusion drives in 2018 with Mojave. Like its predecessor, APFS automatically defragments your drive on the fly, although it works a little differently as it creates snapshots of files so you can access different versions of the same files.

How to defrag a Mac (and why you don't need to)

By Karen Haslam

Back up your Mac before you do anything, because the sudden onset of poor performance without having installed something that might be the culprit is often a symptom of a hard disk drive that is operating in a state of failure.

To learn how to use Time Machine please read Back up your files with Time Machine on Mac.

Don't prematurely conclude the cause of a problem, and especially don't install some magical cure-all claiming to fix something that isn't broken to begin with. As others already pointed out "defragmenting" is a long-outdated practice that has not been applicable to Macs for many years: About disk optimization with Mac OS X - Apple Support.

Are you having a problem for which you think defragging is the answer? Perhaps you should just describe the problem you are having.

If you are just curious because you always did it in Windows:

The OS automatically defragments files on the fly if they are smaller than 20MB*. If you often edit very large files (20+MB), it is possible that it will get fragmented.

If you do that regularly, the way to defragment is to Clone the drive to another, then clone it back.

*I don't know if that is still an accurate size. They may have changed it.

Download and run Etrecheck. Etrecheck is a diagnostic tool that was developed by one of the most respected users here in the ASC and recommended by Apple Support  to provide a snapshot of the system and help identify the more obvious culprits that can adversely affect a Mac's performance.

Copy the report

and use the Add Text button to include the report in your reply. How to use the Add Text Feature When Posting Large Amounts of Text, i.e. an Etrecheck Report

Before running Etrecheck assign Full Disk Access to Etrecheck so that it can get additional information from the Console and log files for the report:

Then we can examine the report and see if we can determine what's causing the problem..

You don't. It is not a Windows operating system. Why do you think it needs a defrag?

reading between the lines here. I know you are being specific but I imagine what you are after is higher performance. Disk Warrior can optimize the directory. It would be an expensive purchase for that single feature.

Getting a little curious I did the following:

iMac:~ admin$ apropos defragment
defragcli(8)             - targeted userspace defragmentation tool
defragx(8)               - targeted userspace defragmenter daemon

SSDs don't need defragmenting.

HDDs generally won't benefit, it's very time consuming and adds heat generation to the device. Overall, the larger the drive, the more data, the more time to defragment; hence defragmenting such a drive would only contribute to the softening of the HDD's lifecycle.

This being said, I think Mac OS does some defragmenting in the background, this is what I understood from years back but never truly verified the claim.

There is no need. A Mac is not a Windows PC. The file system doesn't behave in the same way. There should be no need to defrag.

I think Mac OS does some defragmenting in the background, this is what I understood from years back but never truly verified the claim.

Yes & no, if you did defrag all the files totally as well as the directory in DW, the OSX would immediately start fragmenting them.

Not mentioning the Defrag tools because they don't work with APFS or past 10.13.6

Reinstall your MacOs,when your mac/Imac is slow!

All the rubbish,than," your not running ,a Windows System",you can not use for nothing?

Reinstall your MacOS,from the AppStore,or if your have a, Time Machine BackUp,on an, extern Harddrive!

Some issue on the,SSD Drive,we do not have the information,on that,i Think?

Although the software is free I am not suggesting at all that you install or use it. I just wanted to highlight that a tool was available at one time. Defragmentation is unnecessary nor desired on a Mac.

I hope you take a look at the Macworld article, educate yourself on the topic, even just a little and also check this link, the software is free. https://coriolis-systems.com

And if it's an SSD there is really no need to defrag.