On Feb 1, 2024, at 6:32 AM, Randy B. Singer <randy@...> wrote:


Here is a tip that is simple, easy to implement, but which should be extremely valuable. It only applies if your Macintosh has a solid state drive (SSD). It will be most useful if you have an internal (boot) SSD, but it should also be useful if you have an external SSD.

You can determine if you have an internal SSD (as opposed to a rotating disk hard drive) by going into:
Apple menu --> About This Mac --> System Report --> Hardware --> [click on the disclose triangle to the left of "Hardware" if there isn't a list of stuff under Hardware] --> Storage --> Medium Type
If it says "rotational" you don't have an internal SSD.

I've been researching a problem with Mac SSD's, and that is that they tend to start slowing down when they reach roughly 50% full.

"In practice, an SSD’s performance begins to decline after it reaches about 50% full."





SSD's slow down because when data on your SSD is deleted, the registers that data occupies aren't erased, they are just marked as being available to be re-written. The problem is that once every register in the drive is written to once, it takes several operations to write new data to one of the available locations because there is already data there and it must be erased first. This noticeably slows down drive access.

Why Solid-State Drive (SSD) Performance Slows Down As It Becomes Full


Unfortunately, the Mac OS doesn't have any software tools that can erase full but available registers. (Such tools exist for Windows, so it is frustrating that there isn't something similar for the Macintosh.) I've been researching this, hoping that there might be a Unix command that would do this, but while there are "secure erase" commands (which write zeros or similar to the designated space), there are no Unix commands that will completely erase registers marked as available.

But some sleuthing turned up the fact that most SSD's (or your OS's TRIM function) include "garbage collection" routines. These are routines that do exactly what I was looking for. Garbage collections occurs during times when your Mac is completely idle. The problem is that most Macs are set so that the garbage collection routines never run, even when your Mac is in sleep mode, which would be the most advantageous time for them to run. However, this can easily be remedied!!!

So, to prevent your SSD's performance from degrading you can adjust your Mac's settings to ensure that your SSD stays powered on when your computer goes into sleep mode, which will allow garbage collection to run.

Do this:

- Go into System Preferences (in your Apple menu or in your dock)
- Go into Energy Saver
- Unlock things by clicking on the lock icon on the lower left (if necessary) and putting in your password
- Uncheck: "Put the hard disk(s) to sleep when possible"
- Lock things back up



Your SSD should now retain its full performance even after it is well past 50% full, and it is likely to have a longer service life than it might have previously!


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Randy B. Singer
Co-author of The Macintosh Bible (4th, 5th, and 6th editions)

Essential But Hard To Find Macintosh Software and Advice

__________________________________________________

On Feb 2, 2024, at 09:43, mary via groups.io <mkheadley80503@...> wrote:

?Hi Randy,

Thanks, as always, for your very useful tips! However, I'm afraid all the changes in language used between the various Mac O/S versions has me stumped as to how to set things to have my hard drive powered when my Mac goes to sleep.

When I go to System Settings >? Battery > Options button, I'm confronted with a dialog box that says "Wake for network access. While sleeping, your Mac can receive incoming network traffic, such as iMessages and other iCloud updates, to keep your applications up to date" and then I have to choose between these 3 options: Only on Power Adapter, Always, and Never. So which would I choose?

Thanks,
Mary

On Feb 6, 2024, at 2:17?PM, Bev in TX <countryone77@...> wrote:

On Feb 6, 2024, at 9:39?AM, todhop <hoplist@...> wrote:

I have never had a system where this setting wasn’t a problem, which is why I know the Terminal command for this:

sudo pmset disksleep 0

I’ve had this setting off for years. Its implementation is terrible. It spins drives down constantly, increasing wear and tear, not decreasing it. If you have an SSD system drive and the OS is spinning down your external spinning drives, you offset your speed advantage as the OS is constantly waiting for the HDDs to spin up anytime you access the file system even if the HDD isn’t actually needed. It doesn’t know, so it spins it up. And by the way, your drives will spin down anyway when sleeping, eventually. Many modern externals will spin down on their own when idle, regardless of the OS, and many ignore the OS and spin constantly regardless.

That’s very interesting! ?This command is going into my notebook of useful macOS commands and I’ll be utilizing it because I do have some useful HDDs.

I saw a “caffeinate -m” command, but it doesn’t exit and keeps a window open.

-m ? Create an assertion to prevent the disk from idle sleeping.

?I’m still not convinced as to whether it’s generally applicable to SSDs. ?The Crucial article only mentions this in conjunction with their SSDs. ?I’m waiting for a reply to my questions from Crucial. ?They did reply saying to turn “Put hard disks to sleep when possible” off, even though I told them the option doesn’t show up unless I have a HDD attached. ?So, I’ve repeated my question and am still waiting for a response.

--
Bev in TX