What are your SSD health stats? Is MacOS aggressively idling the SSD?

[powerslave12r]

I noticed that my 2015 rMBP 15" running Mojave has an average of 33 power cycles a day being reported by the tools `DriveDx` and `smartmontools.`

This doesn't seem right at all, as I have not been closing the lid 33 times a day! And yet, when I test it, I see that the count only goes up once each time I close the lid and open it.

Perhaps each time the drive goes to idle increases the count by 1?

But I don't leave the machine idle much. Does MacOS frequently wake up the SSD while in standby to do background tasks?

You could use the software DriveDx or from the Terminal, run:

brew install smartmontool
smartctl -s on -a disk0

Could you please share what these S.M.A.R.T values are on your MBPs ssd?

9 Power_On_Hours
12 Power_Cycle_Count

Thanks!

 

[powerslave12r]

I am wondering if some parameters need to be tweaked using "pmset".

 

[powerslave12r]

Inspecting multiple mbp's running Mojave, I see the SSD SMART data "power cycle count" increases a lot more than the actual times I standby or shutdown.

The count goes up while in standby, with power nap disabled as well.

Does this affect the life of the SSD? This attribute has a lifetime percentage associated with it.

Both DriveDX and smartmontools confirmed this. If you would like to check, you could either install DriveDx (Free demo), or install smartmontools using HomeBrew. (https://brew.sh)

brew install smartmontool
smartctl -s on -a disk0

I'm looking at mainly two values in the SMART data:

9 Power_On_Hours
12 Power_Cycle_Count

Comparing these values a few hours apart will give an idea of the rate of power cycles on the SSD.

If it affects the health of the ssd, I'd like to address it. Given that it's solid state, power cycles probably are harmless, but I don't know.

Any help welcome! Thank you.

 

[BATman.Berlin]

I cannot see a reason why that would affect the life of the SSD. SSD’s don’t have moving parts, therefore it is only the controller going on/off. SSD’s degrade with the amount of write cycles but modern NAND chips have enough redundancy build in to cover for that.
I guess you are ok. I cannot imagine Apple coders would not know how to handle SSD I/O properly.

 

[Fishrrman]

If there's anything that could prematurely wear out an SSD, I think that would be Apple's memory management scheme that loads all the RAM into the OS/System, and then starts "swapping it out" to the drive and back into RAM. This started with Mavericks (10.9), and it's the primary reason why platter-based hard drives became so "slow" with Macs (never-ending page ins and page outs).

If one has enough RAM, and if one is mindful enough to manage how many apps are loaded at once, then you can DISABLE VM disk swapping and just "run with the installed RAM" without the OS trying to "hit the drive" all the time.

That's what I've been doing for several years now.
If I open terminal and type in this command:
(To check if VM is being used):
sysctl vm.swapusage

I get:
vm.swapusage: total = 0.00M used = 0.00M free = 0.00M

Works great.
NO crashes.
(2018 Mini with 16gb RAM)

 

[powerslave12r]

I cannot see a reason why that would affect the life of the SSD. SSD’s don’t have moving parts, therefore it is only the controller going on/off. SSD’s degrade with the amount of write cycles but modern NAND chips have enough redundancy build in to cover for that.
I guess you are ok. I cannot imagine Apple coders would not know how to handle SSD I/O properly.

I agree with you in that the device is solid state and so may be fine overall. It does have a 'total percentage' remaining associated with it in the SMART information that worries me.

If there's anything that could prematurely wear out an SSD, I think that would be Apple's memory management scheme that loads all the RAM into the OS/System, and then starts "swapping it out" to the drive and back into RAM. This started with Mavericks (10.9), and it's the primary reason why platter-based hard drives became so "slow" with Macs (never-ending page ins and page outs).

If one has enough RAM, and if one is mindful enough to manage how many apps are loaded at once, then you can DISABLE VM disk swapping and just "run with the installed RAM" without the OS trying to "hit the drive" all the time.

That's what I've been doing for several years now.
If I open terminal and type in this command:
(To check if VM is being used):
sysctl vm.swapusage

I get:
vm.swapusage: total = 0.00M used = 0.00M free = 0.00M

Works great.
NO crashes.
(2018 Mini with 16gb RAM)

I do see some swap usage with 16GB but I think many modern OSes tend to do that. On linux the swappiness factor is non-zero by default, so even that uses swap even when there's room in memory.

I'm not worried about disk writes to be honest, because those are really hard to hit in the device's lifetime.

I'm more worried about this ridiculous uptick in the power cycle count.

 

[Erehy Dobon]

Personally, I am not going to baby my device.

It's a tool not a piece of jewelry. If I get five years of hard use out of it, that's better than getting 7-10 years of light/paranoid usage.

It's just a stupid computer.

 

[powerslave12r]

Personally, I am not going to baby my device.

I'm with you on that. But I hope you'll agree that troubleshooting odd behavior is not equivalent to babying a device.

 

[Erehy Dobon]

Install a fresh copy of macOS to a blank external drive. Boot off of that. Let it run a couple of days WITHOUT ADDING ANY SKANKWARE. Yes, that includes the Google Chrome web browser and your favorite extensions.

Compare results.

 

[powerslave12r]

Install a fresh copy of macOS to a blank external drive. Boot off of that. Let it run a couple of days WITHOUT ADDING ANY SKANKWARE. Yes, that includes the Google Chrome web browser and your favorite extensions.

Compare results.

The tests are being performed on a fresh install on two different macbook pros. I don't use Chrome.