M1 Mac owners are experiencing extremely high SSD writes over short periods of time, likely thanks to aggressive swap

[Spindel]

29 minutes ago, just_dave said:

what app is that?

DriveDx

[Zifle]

My 3.5 year-old thinkpad, having run linux for work almost daily, is sitting at 19.6TB written over 4863 power on hours. That works out to about 67MB written per minute, if my math isn't terribly off.
Sure, the workload can vary greatly, but it seems quite excessive that a bunch of 2-months old machines would have more writes already (and some by quite some margin), regardless of the exact accuracy of the reporting.

[leadeater]

14 minutes ago, just_dave said:

If you go down the twitter thread, people are posting kernel_task values from their activity monitor. I restarted my Mac and from what i'm seeing so far, it could be a bug related to how long the machine has been last turned on

Others are also saying it's just Mac OS and has been doing this the whole time, maybe just Big Sur though. Still for a lot of these figures to be true the device would essentially have to be writing 100MB/s 24/7 for the last 90 days straight. Seriously just need to open System Monitor and look at live disk usage for a bit, if you don't see any write activity high enough and sustained enough then it's not possible to be writing that much data.

[just_dave]

2 minutes ago, leadeater said:

Others are also saying it's just Mac OS and has been doing this the whole time, maybe just Big Sur though. Still for a lot of these figures to be true the device would essentially have to be writing 100MB/s 24/7 for the last 90 days straight. Seriously just need to open System Monitor and look at live disk usage for a bit, if you don't see any write activity high and enough and sustained enough then it's not possible to be writing that much data.

It's been 3 hrs since I restarted my mac and, have 20 safari tabs open and 4 apps, 3 of which are electron-intel arch. So far 16GB of written data on the drive.

[leadeater]

4 minutes ago, just_dave said:

It's been 3 hrs since I restarted my mac and, have 20 safari tabs open and 4 apps, 3 of which are electron-intel arch. So far 16GB of written data on the drive.

Hmmm I think that works out to be about 11TB over 90 days at that rate, rather high tbh.

 

Has that write I/O basically stay constant so far? No going to any decent idle periods of basically 0?

[just_dave]

2 minutes ago, leadeater said:

Hmmm I think that works out to be about 11TB over 90 days at that rate, rather high tbh.

 

Has that write I/O basically stay constant so far? No doing to any decent idle periods of basically 0?

It keeps spiking between those high numbers and 0 every few hundred ms

[Spindel]

 

For academics computer was started at about 06:30 so 5 hours ago. 

[just_dave]

20 minutes ago, Spindel said:

DriveDx

Shows the same value as smartmontools

[leadeater]

1 minute ago, Spindel said:

For academics computer was started at about 06:30 so 5 hours ago. 

Hmm, well I hope the SSDs have above 0.5 DWPD rating. One of the links in the twitter/reddit (forget which) said they are using NAND with 1.0 DWPD.

[Spindel]

7 minutes ago, just_dave said:

Shows the same value as smartmontools

Yes but I still suspect something is wrong with the reporting tools. 

 

It is impossible for my hard drive to only have 95 power on hours since I got it. Simply can't happen I use the computer actively more than that in a week, even if the disk powers down I have constant disk activity most of the day which would wake it up. 

 

EDIT:// and with disk activity I mean just from autosaves from programs, opening documents and all other normal stuff any computer does. 

[Archer42]

7 minutes ago, Spindel said:

It is impossible for my hard drive to only have 95 power on hours since I got it. Simply can't happen I use the computer actively more than that in a week, even if the disk powers down I have constant disk activity most of the day which would wake it up.

There may be one explanation.

If you look, for example, at intel's smart attribute description, power on hours do not include some power saving states.

Also if you use something that's accessing ssd, depending on os settings it might still spend most of the time in power saving mode. Everything is cached nowadays, and if writes are, for example, committed only once every few seconds and reads are cached...

[Spindel]

10 minutes ago, Archer42 said:

There may be one explanation.

If you look, for example, at intel's smart attribute description, power on hours do not include some power saving states.

Also if you use something that's accessing ssd, depending on os settings it might still spend most of the time in power saving mode. Everything is cached nowadays, and if writes are, for example, committed only once every few seconds and reads are cached...

But it is impossible for the hard drive to only have been active on average 1 hour per day since I got it. 

[Arika]

At this point it's less a question of

"are these SSDs actually writing multiple GB a minute?"

 

and more

 

"are these SSDs going to behave like they have been writing multiple GB a minute?"

 

Therefore is it really going to matter if they were or weren't? If they are being reported internally at these numbers it is going to start sectioning off portions regardless if it's actually doing it.

 

[just_dave]

Just now, Arika S said:

At this point it's less a question of

"are these SSDs actually writing multiple GB a minute?"

 

and more

 

"are these SSDs going to behave like they have been writing multiple GB a minute?"

 

Therefore is it really going to matter if they were or weren't? If they are being reported internally at these numbers it is going to start sectioning off portions regardless if it's actually doing it.

 

doesnt the controller check for bad blocks first? if they are not actually writing this much data, then the cells shouldn't be getting corrupted/worn out and the controller wouldn't have a reason to replace them

[Archer42]

3 minutes ago, Spindel said:

But it is impossible for the hard drive to only have been active on average 1 hour per day since I got it.

Easily possible IMO.

Since SSD transitions between power saving modes relatively quickly it will use every fraction of a second when it is not being accessed to save power. Especially in a laptop I'd expect it to be configured pretty aggressively.

[Arika]

3 minutes ago, just_dave said:

doesnt the controller check for bad blocks first? if they are not actually writing this much data, then the cells shouldn't be getting corrupted/worn out and the controller wouldn't have a reason to replace them

depends what the OS is reporting to the SSD and whether the SSD is just accepting regardless of the true number of writes

 

The easiest way to check would be to remove the SSD and connect it to another system and run the test again to avoid any OS specific numbers....oh wait.

[just_dave]

12 minutes ago, Arika S said:

depends what the OS is reporting to the SSD and whether the SSD is just accepting regardless of the true number of writes

 

The easiest way to check would be to remove the SSD and connect it to another system and run the test again to avoid any OS specific numbers....oh wait.

 

[leadeater]

17 minutes ago, Arika S said:

depends what the OS is reporting to the SSD and whether the SSD is just accepting regardless of the true number of writes

 

The easiest way to check would be to remove the SSD and connect it to another system and run the test again to avoid any OS specific numbers....oh wait.

That's not how it works, the OS doesn't tell the SSD how to manage it's own memory cells beyond issuing a TRIM command. The SSD controller and firmware monitors what cells are active with data in them and how many times it's written a cell, SSDs actively lie to the OS about where data actually is because filesystems still work on HDD layout and terminology which SSDs just do not use.

[leadeater]

32 minutes ago, Archer42 said:

Easily possible IMO.

Since SSD transitions between power saving modes relatively quickly it will use every fraction of a second when it is not being accessed to save power. Especially in a laptop I'd expect it to be configured pretty aggressively.

 

Power on hours for my SSD is ~57,000 hours, I think I got it in 2014 so 7 years. That's about 22 hours per day which is actually likely correct as I never turn my computer off and margin of error for when I actually purchased the computer. Definitely times where my PC is 'idle'.

[Spindel]

First I have to start with saying that I don't think this is a big deal. But of course the Apple BAD trolls jump on anything. 

 

Secondly there is something wrong with the disk reporting tools (look at previous posts on my power on status for the SSD).

 

But the more I look at this it becomes more intriguing. There is something going on here on OS level and I don't think most of us have a clue what it is. 

 

Se picture below, computer started at about 06:30 and it's now 13:00

 

Why has install deamon written 11,5 GB?

There has been some app updates today but nowhere near that size. 

 

Why is backup reported to have written 8,72 GB?

I backup through TM to my NAS, the number itself probably is correct but not a chance it has written it to the SSD. 

 

Why has OneDrive written 6,5 GB to disk? 

I only run on-demand, so files are offline until I need them, I have not worked on that many documents today. 

 

Why has Outlook written almost 900 MB?

For reference I have my personal mail accounts through the default mail app and it has only written about 3 MB to disk.

 

As a referens this is memory usage, "växelfil" = swap

 

 

The plot thickens, it's almost as if people have no clue what is normal and how OSs handle things. 

[just_dave]

10 minutes ago, Spindel said:

First I have to start with saying that I don't think this is a big deal. But of course the Apple BAD trolls jump on anything. 

 

Secondly there is something wrong with the disk reporting tools (look at previous posts on my power on status for the SSD).

 

But the more I look at this it becomes more intriguing. There is something going on here on OS level and I don't think most of us have a clue what it is. 

 

Se picture below, computer started at about 06:30 and it's now 13:00

 

Why has install deamon written 11,5 GB?

There has been some app updates today but nowhere near that size. 

 

Why is backup reported to have written 8,72 GB?

I backup through TM to my NAS, the number itself probably is correct but not a chance it has written it to the SSD. 

 

Why has OneDrive written 6,5 GB to disk? 

I only run on-demand, so files are offline until I need them, I have not worked on that many documents today. 

 

Why has Outlook written almost 900 MB?

For reference I have my personal mail accounts through the default mail app and it has only written about 3 MB to disk.

 

As a referens this is memory usage, "växelfil" = swap

 

 

The plot thickens, it's almost as if people have no clue what is normal and how OSs handle things. 

Same story here. I restarted the mac at 9:00. So far, Activity Monitor shows 19GB of data written. The Memory page shows 0 byte swap as well.

The SMART diagnostic went up 20GB since the restart (I checked it right after).

Processes with most written data:

installd - 7.92 GB

appstoreagent - 4.0 GB

launchd - 1.03 GB

Safari - 1.38 GB

kernel_task - 929.4 MB

[AlTech]

3 hours ago, Froody129 said:

Man, that sucks. Especially if you've bought a smaller drive size and using an external one for example. Can you not just adjust the page file size like on Windows?

No, that’s under macOS’s control but the amount of swapping even under 16GB RAM is painful.

 

I don’t have an M1 Mac so I don’t know if it’s different but 16GB on an Intel Mac is barely enough. 8GB would require basically non-stop paging.

[Spindel]

1 minute ago, AluminiumTech said:

No, that’s under macOS’s control but the amount of swapping even under 16GB RAM is painful.

 

I don’t have an M1 Mac so I don’t know if it’s different but 16GB on an Intel Mac is barely enough. 8GB would require basically non-stop paging.

Of course this is workflow dependent. 

 

But for me I almost never swap, happends now and then, it has mainly happened when OneDrive (which really is a crap piece of software) goes of the rails and starts to hog RAM (max I've seen it take up before I stopped it was 19 GB). 

[just_dave]

7 minutes ago, AluminiumTech said:

No, that’s under macOS’s control but the amount of swapping even under 16GB RAM is painful.

 

I don’t have an M1 Mac so I don’t know if it’s different but 16GB on an Intel Mac is barely enough. 8GB would require basically non-stop paging.

The thing is, it doesn't seem to be swap. My swap file has been 0 bytes since I restarted the machine, yet 20GB of something have been written to the SSD.

[suicidalfranco]

First thing i did to my MBP when i upgraded it's RAM to 16GB and the HDD to an SSD was disable SWAP. Was useful back in the 4GB or ram days, don't see a point in it when 8 became the norm