ssd swap - high usage of Terabytes Written

[tab0reqq]

Another update. Still not looking good.

jarek@MacBook-Air-Jarosaw ~ % clear

jarek@MacBook-Air-Jarosaw ~ % uptime    
12:00  up 17:59, 2 users, load averages: 1,90 1,89 1,84
jarek@MacBook-Air-Jarosaw ~ % last reboot
reboot    ~                         Tue Mar  2 18:02
reboot    ~                         Fri Feb 26 19:42

wtmp begins Fri Feb 26 19:42
jarek@MacBook-Air-Jarosaw ~ % vm_stat     
Mach Virtual Memory Statistics: (page size of 16384 bytes)
Pages free:                                3740.
Pages active:                            406382.
Pages inactive:                          395511.
Pages speculative:                           21.
Pages throttled:                              0.
Pages wired down:                        103147.
Pages purgeable:                           1611.
"Translation faults":                  54576674.
Pages copy-on-write:                    1327606.
Pages zero filled:                     31509429.
Pages reactivated:                      7796450.
Pages purged:                            771449.
File-backed pages:                       266845.
Anonymous pages:                         535069.
Pages stored in compressor:              926927.
Pages occupied by compressor:             97890.
Decompressions:                         5126573.
Compressions:                           7628824.
Pageins:                                1834886.
Pageouts:                                 49960.
Swapins:                                2057203.
Swapouts:                               2462613.

 

[pistonpilot]

My uptime on my Intel Mac is 2 days:

42GB is acceptable. I disabled Spotlight. Prior to that, it was writing more than 2TB in a day.

kernel_task 204.74 GB 49.22 GB 0 root 3.4 1:38:50.25 (null) 0.0 0.00 (null) - No No 0 bytes 0 bytes 0 bytes 0 bytes Intel No No Yes 0 bytes 0 0 bytes 0 0 bytes 0 bytes (null)
launchd 6.22 GB 156.5 MB 1 root 0.1 8:53.72 (null) 0.0 0.00 (null) - No No 0 bytes 0 bytes 0 bytes 0 bytes Intel No No Yes 0 bytes 0 0 bytes 0 0 bytes 0 bytes (null)
backupd 27.96 GB 64.78 GB 279 root 0.0 28:59.15 (null) 0.0 0.00 (null) - No No 0 bytes 0 bytes 0 bytes 0 bytes Intel Yes No Yes 0 bytes 0 0 bytes 0 0 bytes 0 bytes (null)
mds_stores 7.45 GB 6.41 GB 530 root 0.0 5:09.40 (null) 0.0 0.00 (null) - No No 0 bytes 0 bytes 0 bytes 0 bytes Intel No Yes Yes 0 bytes 0 0 bytes 0 0 bytes 0 bytes (null)
Code42Service 6.45 GB 230.01 GB 110 root 160.2 42:46:08.56 (null) 0.0 0.00 (null) - No No 0 bytes 0 bytes 0 bytes 0 bytes Intel No No No 0 bytes 0 0 bytes 0 0 bytes 0 bytes (null)

 

[pistonpilot]

Swap hasn't been identified as the issue yet. The SSD is no longer replaceable because the NVME controller is part of the M1 SoC. Only the flash memory remains external. Apple could have put that on a daughter-board but that would be proprietary and possibly entail some engineering tradeoffs and add cost.

The SSD portion of my Fusion Drive on Intel iMac is not replaceable by me. Funny, it was just replaced 2 weeks ago and now has almost 2TB written to it. It is 128GB in size. That's impressive.

 

[qap]

Good point, though as far as I can tell it's not just a factor of 4 - kernel_task just keeps writing to the swap continuously even if the memory is available, i.e. the memory management algorithm is broken.

...but the swap file doesn't increase, that's the absurd thing! So what the hell is writing? zeros? 😤

Anyway, if someone want to try, you can disable the paging i/o (swap) by unloading the responsable daemon:

sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.dynamic_pager.plist

(use load -w to re-enable it) I have no idea of how macOS can react to this...

The swap file should be in /private/var/vm/

At the moment I'm on iMac and I don't have swap size (since I have 64Gb of ram 😅 )

Home@Giulio-iMac ~ % uptime && ls -lh /private/var/vm/

12:21  up  3:25, 2 users, load averages: 1.15 1.05 1.00

total 4194304

-rw------T  1 root  wheel   2.0G Mar  3 08:56 sleepimage

I want to understand what the kernel task is writing (reading is not a trouble, but if it reads, it has already written something in theory)

 

[Tenkaykev]

Amen brother. Having had 5 iMac replacements courtesy of AppleCare I can tell you that you are spot on. Apple's hardware sucks. I suspect that both my Intel iMac and Silicon Mac Mini will be replaced, as both have AppleCare and I know the head of USA Customer Relations.

Apple should pull their manufacturing from China immediately. The reliability is sorely lacking.

I'm genuinely curious, no snark. If your opinion of Apple hardware is that it "sucks" I take it that it is necessary for your job? Otherwise why not use Windows / Linux ?

 

[sammy2066]

Those TBW numbers seem very high. I've been using a Samsung 950 Pro SSD as my primary boot drive in my desktop since I built it in 2005. I'm also a Windows Insider (Fast/Dev ring), so typically install 2-3 new builds every month, on average. Samsung Magician only shows 36 TB written - doesn't that seem excessively low? Or am I missing something?

 

[pistonpilot]

I disabled Spotlight using sudo mdutil -a -i off

on my Silicon Mac Mini

It was purchased in January.

 

[pistonpilot]

I'm genuinely curious, no snark. If your opinion of Apple hardware is that it "sucks" I take it that it is necessary for your job? Otherwise why not use Windows / Linux ?

I prefer to use OSX. I would like the hardware to be so much better than it is. There have been too many repairs made to my Apple products but also to my clients' Apples.

I am a Mac/Windows/Linux expert. I make my money fixing Windows. Windows sucks, but I can choose the hardware I want to use for both Linux and Windows.

I am an independent consultant and a damn good one. I find it easier to use OSX. It is a preference and nothing more. If I had to buy an Apple product, I would not. I think the hardware is crap. That is also my opinion. By the way, my bonafides are decades in this business.

If I did not continue to get free replacements thanks to AppleCare, I would buy a business-grade PC and run Linux.

I purchased my first iMac in 2008. It was a 21" and it and its replacements have been changed 5 times since 2008. I have two years left on this iMac's AppleCare and it was serviced 2 weeks ago, and it was hours away from my 6th replacement.

I'm sure I will get another shot or two at replacing this one and that replacement will be a Silicon iMac for this very worthy i9 Intel iMac.

Again, the hardware reliability is crap. It cost me at least an entire day of productivity and probably more.

Crap.

Crap I say, Damn your Eyes Apple!

 

[theSeb]

Those TBW numbers seem very high. I've been using a Samsung 950 Pro SSD as my primary boot drive in my desktop since I built it in 2005. I'm also a Windows Insider (Fast/Dev ring), so typically install 2-3 new builds every month, on average. Samsung Magician only shows 36 TB written - doesn't that seem excessively low? Or am I missing something?

I assume you mean 2015 based on the drive you mention? No, it depends on use and seems perfectly average.

 

[Tenkaykev]

I prefer to use OSX. I would like the hardware to be so much better than it is. There have been too many repairs made to my Apple products but also to my clients' Apples.

I am a Mac/Windows/Linux expert. I make my money fixing Windows. Windows sucks, but I can choose the hardware I want to use for both Linux and Windows.

I am an independent consultant and a damn good one. I find it easier to use OSX. It is a preference and nothing more. If I had to buy an Apple product, I would not. I think the hardware is crap. That is also my opinion. By the way, my bonafides are decades in this business.

If I did not continue to get free replacements thanks to AppleCare, I would buy a business-grade PC and run Linux.

I purchased my first iMac in 2008. It was a 21" and it and its replacements have been changed 5 times since 2008. I have two years left on this iMac's AppleCare and it was serviced 2 weeks ago, and it was hours away from my 6th replacement.

I'm sure I will get another shot or two at replacing this one and that replacement will be a Silicon iMac for this very worthy i9 Intel iMac.

Again, the hardware reliability is crap. It cost me at least an entire day of productivity and probably more.

Crap.

Crap I say, Damn your Eyes Apple!

Have you been tempted to go down the "Hackintosh" route?

 

[pistonpilot]

Have you been tempted to go down the "Hackintosh" route?

If I still lived in the USA and had access to a proper computer store, I might.

 

[ovenbakedlies]

Yesterday morning I did some light browsing (only). My Mac mini M1 (8/256) found reason to write 11Gb to the hard drive.

In the afternoon, I fired up a couple of apps. The main one (and most memory intensive) runs under Rosetta. And its an Electron App, using Chromium. Neither write any local data at all. My memory usage goes up but never out of the 'green' pressure zone.

6 hours later I've now written over 1.3 TB to the drive. On average, that means every byte/cell on the drive has been written to 5 times. Virtually all of it due to the O/S.

Sometimes I get delay switching between the apps (occasional beachball). I am guessing its due to insane amounts of swap management going on. (but as said, always 'green' zone).

This is just nuts, and I think that Apples memory / swap management is........ over-rated. And I'm being extremely polite about that.

I'm going to try disabling spotlight and repeating the same workflow. But I think something may be especially not right with rosetta apps?

 

[pistonpilot]

Yesterday morning I did some light browsing (only). My Mac mini M1 (8/256) found reason to write 11Gb to the hard drive.

In the afternoon, I fired up a couple of apps. The main one (and most memory intensive) runs under Rosetta. And its an Electron App, using Chromium. Neither write any local data at all. My memory usage goes up but never out of the 'green' pressure zone.

6 hours later I've now written over 1.3 TB to the drive. On average, that means every byte/cell on the drive has been written to 5 times. Virtually all of it due to the O/S.

Sometimes I get delay switching between the apps (occasional beachball). I am guessing its due to insane amounts of swap management going on. (but as said, always 'green' zone).

This is just nuts, and I think that Apples memory / swap management is........ over-rated. And I'm being extremely polite about that.

I'm going to try disabling spotlight and repeating the same workflow. But I think something may be especially not right with rosetta apps?

Why have you focussed on Rosetta?

 

[Isamilis]

The SSD portion of my Fusion Drive on Intel iMac is not replaceable by me. Funny, it was just replaced 2 weeks ago and now has almost 2TB written to it. It is 128GB in size. That's impressive.

Are you using Big Sur?

 

[Falcon9]

FWIW my M1 Pro (8/512) has written 120 GB to the disk since last boot 5 days 12 hrs ago. This does not seem unreasonable to me. I've used the computer for a variety of tasks for several hours each day too, so it has not just been sitting idle.

 

[ovenbakedlies]

Why have you focussed on Rosetta?

Simply because when I fire up the Chromium app which runs under Intel architecture, my hard drive writes seem to go ballistic.

 

[pistonpilot]

Are you using Big Sur?

Yes. I upgraded because of my Mac Mini - I didn't want to do it. I was still happily running Mojave. I think Big Sur like Apple Hardware, is crap.

 

[Isamilis]

Yes. I upgraded because of my Mac Mini - I didn't want to do it. I was still happily running Mojave. I think Big Sur like Apple Hardware, is crap.

It looked like there are problems with Big Sur and/or with M1. My intel MBA 2020, bought in Aug last year (6 months old) has TBW around 3 TB, which considered still normal. Most of the time using Catalina, only 1.5 months I tested Big Sur before downgraded back to Catalina due to slow & sluggish. Maybe downgraded back to Catalina (if possible) can avoid more excessive wear.

 

[alien3dx]

I prefer to use OSX. I would like the hardware to be so much better than it is. There have been too many repairs made to my Apple products but also to my clients' Apples.

I am a Mac/Windows/Linux expert. I make my money fixing Windows. Windows sucks, but I can choose the hardware I want to use for both Linux and Windows.

I am an independent consultant and a damn good one. I find it easier to use OSX. It is a preference and nothing more. If I had to buy an Apple product, I would not. I think the hardware is crap. That is also my opinion. By the way, my bonafides are decades in this business.

If I did not continue to get free replacements thanks to AppleCare, I would buy a business-grade PC and run Linux.

I purchased my first iMac in 2008. It was a 21" and it and its replacements have been changed 5 times since 2008. I have two years left on this iMac's AppleCare and it was serviced 2 weeks ago, and it was hours away from my 6th replacement.

I'm sure I will get another shot or two at replacing this one and that replacement will be a Silicon iMac for this very worthy i9 Intel iMac.

Again, the hardware reliability is crap. It cost me at least an entire day of productivity and probably more.

Crap.

Crap I say, Damn your Eyes Apple!

you may good but most of the client open a computer also scare doesnt care gender last time me.For me as long time user computer, apple way long to be like linux and windows usability.

 

[qap]

...but the swap file doesn't increase, that's the absurd thing! So what the hell is writing? zeros? 😤

Anyway, if someone want to try, you can disable the paging i/o (swap) by unloading the responsable daemon:

sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.dynamic_pager.plist

(use load -w to re-enable it) I have no idea of how macOS can react to this...

The swap file should be in /private/var/vm/

At the moment I'm on iMac and I don't have swap size (since I have 64Gb of ram 😅 )

Home@Giulio-iMac ~ % uptime && ls -lh /private/var/vm/

12:21  up  3:25, 2 users, load averages: 1.15 1.05 1.00

total 4194304
-rw------T  1 root  wheel   2.0G Mar  3 08:56 sleepimage

I want to understand what the kernel task is writing (reading is not a trouble, but if it reads, it has already written something in theory)

I'm replying to myself since I just discovered that macOS compiled for ARM uses a different location for the swap files, now is locate in /System/Volumes/VM

Home@Giulio-MacBook-Air ~ % uptime && ls -lh /System/Volumes/VM
15:37  up  7:06, 2 users, load averages: 0.91 1.00 1.08
total 4194304
-rw-------  1 root  wheel   1.0G Mar  3 08:35 swapfile0
-rw-------  1 root  wheel   1.0G Mar  3 14:53 swapfile1

Anyway this is weird because Disk Utility reports only 789MB of swap, but there are two files of 1GB on the disk (and 6.73GB written by kernel_task process).

I have no idea of what's going on but to me looks weird.

 

[rui no onna]

Those TBW numbers seem very high. I've been using a Samsung 950 Pro SSD as my primary boot drive in my desktop since I built it in 2005. I'm also a Windows Insider (Fast/Dev ring), so typically install 2-3 new builds every month, on average. Samsung Magician only shows 36 TB written - doesn't that seem excessively low? Or am I missing something?

The figures you have look normal. I come from Windows, too, so I was pretty surprised with the high write figures when I got my M1 Mac.

Looking at the CrystalDiskInfo history for my previous and current boot drives, my old drive was at 22.6 TiB writes after 3.2 years and my current drive is just at 11.8 TiB after 2.5 years. Initial setup looks to be around 240 GiB.

 

[theSeb]

...but the swap file doesn't increase, that's the absurd thing! So what the hell is writing? zeros? 😤

Well it's writing and erasing as it's going between memory and the drive. I do wonder whether the absurdly high TBW could be a result of the seemingly increased propensity of the OS to compress pages, thus writing and deleting a lot more than previously and the SSD's controller TRIM algorithm is not working as it should.

 

[qap]

Well it's writing and erasing as it's going between memory and the drive. I do wonder whether the absurdly high TBW could be a result of the seemingly increased propensity of the OS to compress pages, thus writing and deleting a lot more than previously and the SSD's controller TRIM algorithm is not working as it should.

But is not doing this since the swap file remains the same, it doesn't increase or decrease. Maybe macOS is moving from disk to ram and ram to disk alone without reasons (and this is a bug).

Plus swap memory indeed shouldn't be allocated again to ram very often, is not the purpose of swap. If an app needs memory often, it should be placed in ram and use it.

Something is not working as expected on macOS ARM.

 

[theSeb]

But is not doing this since the swap file remains the same, it doesn't increase or decrease. Maybe macOS is moving from disk to ram and ram to disk alone without reasons (and this is a bug).

Plus swap memory indeed shouldn't be allocated again to ram very often, is not the purpose of swap. If an app needs memory often, it should be placed in ram and use it.

Something is not working as expected on macOS ARM.

The file is allocated as that size and it stays constant. Stuff is written and removed from it and the file size will remain constant. This is the same behaviour on Intel Macs

 

[vcsyc]

Pals with very high daily TBW, can you comment on the apps do use?
Do you use Intel apps? Could you re-test your machines without any Intel apps running?