Sleep with an SSD using APFS?

[titangears]

Will putting my Mac to sleep running MacOS 10.13.6 wear out my SSD? Are there any tips that I should do to keep my SSD healthy? For example, one of the things I do in Linux I set noatime in /etc/fstab on my SSD device. Any tips, links, etc would be appreciated.

 

[simonsi]

These days you don't need to do anything the SSD will outlast the device it is in and possibly yourself. Putting something to sleep generally never wears it out - do you think your Mac writes TB of data while asleep?

 

[kohlson]

I have APFS on both 2009 cMP with SSD, and 2013 15-MBP. They both go to sleep and wake up as expected. I have no worries that this will wear out the SSD in either case.

 

[treekram]

I think the concern of the OP is that going to sleep writes the RAM contents to the SSD, and if you're using 16GB (actually USING 16GB, not configured with) and go to sleep often during the course of the day, the number of erase/write cycles can increase to the point where it will make a noticeable impact on how long the SSD will last.

To me at least, Apple's attitude in this respect seems to be, "don't worry, be happy" (don't sweat the details - we won't tell you anyway - let Parent Apple manage for this for you).

Take a look at the following article:
https://www.lifewire.com/change-mac-sleep-settings-2260804

For the OP, your signature indicates a 2011 Mac Mini. Is this what you're using?

Check to see what your hibernate mode is - if it's 0 (what it should be for the Mini), it shouldn't enter hibernation. Just "regular" sleep shouldn't write the RAM contents to disk, it's hibernation that does so (there's also "safe sleep" but that's considered to be the combination of hibernation and keeping power to the RAM chips).

That being said, on my two Mini's (2012, 2014), both upgraded to High Sierra in the past couple of months, I have a sleepimage file of 2GB. I don't know why this is there since I never enter sleep manually. It may just be some sort of default file since the file dates are about when High Sierra was installed and since the files on the two Mini's are the same size. These files are also protected by SIP - they can't be deleted if you have SIP on. For the Mini, in System Preferences -> Energy Saver, on my 2014 Mini, there is checkbox for "Prevent computer from sleeping automatically when the display is off". On my 2012 Mini, I don't have this check box, but I do have a slider which controls computer sleep. Now, if hibernation is off, it shouldn't write to the sleepimage file anyway, but these options are there.

If you have a laptop, my understanding is that it doesn't go into hibernation immediately. On my 2012 MBP (Sierra), which I close the cover for short periods of time when I'm not using it (if I'm not going to use it for hours, I'll turn it off), it hasn't written the sleepimage file in over a month, so for me, that's acceptable.

 

[simonsi]

Nah - 50GB per day, for EVERY day for somewhere between 10 and 40 years is (eg) Crucial's SSD specs...so even several <hibernations> per day (who would do that?), isn't going to appreciably shorten the useful life the OP will get.

I have two Crucial 1TB SSDs in my MBP - 1 is ~2yrs old and is still showing 100% lifetime according to DriveDX, the other is a year older and down to 99%.

 

[treekram]

For the Crucial MX500 500GB, endurance is 180TBW, or about 99GB/day over 5 years. For the Samsung 860 Evo 500GB, it's an incredible 300TBW, or about 164GB/day over 5 years. So if you have one of these SSD's at these sizes (or higher), you can probably hibernate all you want and still have plenty of SSD life at the end of 5 years. (Keep in mind endurance tends to be proportional to SSD capacity.)

So how often does a laptop hibernate? This is the thing that gets me. You have to search a little bit and then you find there's a power management setting that's not readily accessible to the user to figure out how long it is before a computer goes into hibernation (which is referred to as "standbydelay") - for my mid-2012 MBP, it's set to 70 minutes. (The command to use in terminal is "pmset -g" and look for "standbydelay".) Also, if the OP is still concerned about this (since the OP was asking about settings regarding sleep and SSD usage) - and I didn't know this until I was perusing the pmset man page (and how many people do that?) is:

"On desktops that support standby a hibernation image will be written after the specified standbydelay time. To disable hibernation images completely, ensure hibernatemode, standby and autopoweroff are all set to 0."

(You need to use the command line to do this. I'll might try this on one of my High Sierra Mini's to see if it gets rid of the sleepimage file.)

 

[titangears]

Thanks for all the help here. To answer an earlier question, I am indeed running a Mac Mini 2011, and running "pmset -g" returns the following:

System-wide power settings:
Currently in use:
hibernatemode 0
womp 1
networkoversleep 0
sleep 25 (sleep prevented by coreaudiod)
Sleep On Power Button 1
ttyskeepawake 1
hibernatefile /var/vm/sleepimage
autorestart 0
disksleep 10
displaysleep 10 (display sleep prevented by coreaudiod)


So it appears that my memory isn't written to disk. However, based on what I've read here, even if it were written to disk modern SSDs are tough enough to take it for a long time.

Of note, since I do not have an Apple SSD I still had to turn on the SSD Trim manually by running "trimforce enable". Apple did not turn it on automatically for my Samsung 850 EVO. Trim is definitely important, and turning it on was the first thing I did after installing High Sierra on it.

Again, thanks for all the help.