ssd swap - high usage of Terabytes Written

[Peterbeau]

A youtuber said in a video that rosetta (using intel apps) is also one of the causes for excessive swap usage. Does anyone know if rosetta still causes excessive swap usage in 11.4?
I am a broke college student with a passion for music, which means that I can only afford an 8+256 MBA and I will use a lot of rosetta-translated applications, I wonder whether this will affect the life span of my ssd.
Thanks in advance.

 

[Kung gu]

A youtuber said in a video that rosetta (using intel apps) is also one of the causes for excessive swap usage. Does anyone know if rosetta still causes excessive swap usage in 11.4?
I am a broke college student with a passion for music, which means that I can only afford an 8+256 MBA and I will use a lot of rosetta-translated applications, I wonder whether this will affect the life span of my ssd.
Thanks in advance.

Its fixed in 11.4.

There is less writes and less swap being in used in 11.4. I'd say go for the buy. Update to 11.4 when you get your Mac.

 

[ambient_light]

Some updates: while the swap behavior improved gradually in 1.4 for most of the usage scenarios, the problem is not fixed completely. As soon as swap file size reaches some threshold (higher than 5Gb), the "swap storm" might be still triggered and produce a lot of writes. I observed it this week on 11.5b1, when the swap size got into the range of 6-9Gb, and kernel_task suddenly generated 800Gb of writes from swaping. Normally it's ca 50Gb/day.

 

[Kung gu]

Some updates: while the swap behavior improved gradually in 1.4 for most of the usage scenarios, the problem is not fixed completely. As soon as swap file size reaches some threshold (higher than 5Gb), the "swap storm" might be still triggered and produce a lot of writes. I observed it this week on 11.5b1, when the swap size got into the range of 6-9Gb, and kernel_task suddenly generated 800Gb of writes from swaping. Normally it's ca 50Gb/day.

Then you need more RAM. How RAM do you currently have because it's clearly not enough?

Because with 11.4 and onwards, most of the RAM is used and then it uses swap. This was not case with before 11.4 where swap was without filling up most of the RAM.

So if you still see swap of 6-9GB then you are RAM deprived.

 

[ambient_light]

Then you need more RAM. How RAM do you currently have because it's clearly not enough?

Because with 11.4 and onwards, most of the RAM is used and then it uses swap. This was not case with before 11.4 where swap was without filling up most of the RAM.

So if you still see swap of 6-9GB then you are RAM deprived.

It's not the point of getting more RAM (I have 16gb). It's about erratic behavior of the swap algorithm, and the recent statement, that kernel bug in memory management was fixed. It was not.

 

[Kung gu]

It's not the point of getting more RAM (I have 16gb). It's about erratic behavior of the swap algorithm, and the recent statement, that kernel bug in memory management was fixed. It was not.

It was for the most part because 11.4 did certainly fix most cases. there is many posts here and on twitter. The guy who found the buy in the first place says its fixed in 11.4.

 

[leman]

it was. there is many posts here and on twitter. The guy who found the buy in the first place says its fixed in 11.4.

@ambient_light in a post above directly shows an example where it is apparently not yet fixed. Sure, it sounds like a fairly rare corner case, but Apple's work is not done yet.

I would love to see a technical analysis of the kernel changes in 11.4 with a discussion on what was causing the issue. My suspicion is that speculative page offloading goes berserk under certain conditions and continuously writes pages to the SSD over and over and over again.

 

[Kung gu]

It's not the point of getting more RAM (I have 16gb). It's about erratic behavior of the swap algorithm, and the recent statement, that kernel bug in memory management was fixed. It was not.

Ok then in your view what was fixed in 11.4 that resulted in users seeing less writes and less swap?

Because in 11.4 RAM is used first then macOS makes use of swap. This leads to memory pressure being higher than previous macOS builds.

Apple had do something in 11.4 because before physical RAM was not even utilised properly and macOS excessively swapped.

Again your use case might be extreme, I say this because because you are on 11.5. That means your memory being used is around 14GB-15GB because you have 16GB RAM. You said the swap is around 6GB and this is when kernel_task writes to the disk excessively, what is your memory pressure like when this happens?

 

[leman]

Ok then in your view what was fixed in 11.4 that resulted in users seeing less writes and less swap?

Bugs like these can be subtle and complex. It is often that you fix one thing but break another one, or maybe fix all but 1% of edge cases. The evidence that 11.4 has mostly fixed the issue is obvious, which is great news. But there is also some evidence that it didn't fix it completely...

 

[pshufd]

Then you need more RAM. How RAM do you currently have because it's clearly not enough?

Because with 11.4 and onwards, most of the RAM is used and then it uses swap. This was not case with before 11.4 where swap was without filling up most of the RAM.

So if you still see swap of 6-9GB then you are RAM deprived.

I completely agree. One approach would be to get two devices and split the workload between the two of them. I considered doing this (getting two minis as I run with four monitors) but it would be easier to just wait for the M1X which might support four monitors but I'm sure will support at least three.

My 64 GB of RAM arrived yesterday and I popped it into my desktop and it has 128 GB of RAM. It didn't swap at all with 64 GB but I want to run more Virtual Machines while avoiding SWAP. My Late 2009 iMac has 16 GB of RAM. This is 2021 where systems should have more RAM. I mean, why not?

 

[leons]

Activity Monitor>Disk>Data Written
Take note of the number between a set number of days (without rebooting)

 

[Mike Boreham]

Activity Monitor>Disk>Data Written
Take note of the number between a set number of days (without rebooting)

......without externals attached. The AM number includes data written to externals.

Or physically disconnect (not just unmount) externals at the start and end of the test period.

 

[jordysak]

What an awesome find. Thanks for posting this. We finally have an Apple endorsed reading of the SMART data. Not that there was any doubt in my mind anyway but it is great to have ultimate confirmation.

I did not download smarmontools or other third party apps but I used the method explained above to check my SSD wear (via CONSOLE). Here’s the screenshot below. I’m assuming the info I’m looking for is “com.apple.message.smart_data_unites_written: 1139380”.
So 1139380GB (1.140TB) since purchase?

Macbook Pro 16 GB M1 , 23 days old. Is this high wear?

 

[jdb8167]

I did not download smarmontools or other third party apps but I used the method explained above to check my SSD wear (via CONSOLE). Here’s the screenshot below. I’m assuming the info I’m looking for is “com.apple.message.smart_data_unites_written: 1139380”.
So 1139380GB (1.140TB) since purchase?

Macbook Pro 16 GB M1 , 23 days old. Is this high wear?

No multiply the data units written by 512 and then divide by 1,000,000,000.

(1139380*512)/1000000000 = 0.58 TB

No this isn't high. Perfectly normal.

 

[jordysak]

No multiply the data units written by 512 and then divide by 1,000,000,000.

(1139380*512)/1000000000 = 0.58 TB

No this isn't high. Perfectly normal.

Thank you for replying. I should have specified that I have the 256GB model, do I still multiply the number by 512 or should I multiply it by 256?

 

[jdb8167]

Thank you for replying. I should have specified that I have 256GB model, do I still multiply the number by 512 or should I multiply it by 256?

512 bytes per data unit multiplied by 1000. So each data unit represents 512,000 bytes.

 

[jordysak]

512 bytes per data unit multiplied by 1000. So each data unit represents 512,000 bytes.

Okay so divide it by 512 even if my MacBook has 256GB of memory. Thanks for clarifying.

I should add that this is 0.58TB in 23 days, MacBook Pro M1 256GB. Admittedly, I have not used my MacBook to its full extent yet (I will be video editing/music making soon) and will check again on the SSD situation but as of now, with my light usage of web browsing and email this usage doesn’t seem too bad.
That being said , I do have 20-30GB of writes each day if checked via activity monitor, which are still high compared to previous MacBooks.
Oh and I haven’t updated to macOS 11.4 yet, I want to wait a bit before jumping to it, as I’m still hearing some stuff about increased RAM consumption.
Current macOS 11.2.3 (the one it came with).

 

[Kung gu]

Okay so divide it by 512 even if my MacBook has 256GB of memory. Thanks for clarifying.

I should add that this is 0.58TB in 23 days, MacBook Pro M1 256GB. Admittedly, I have not used my MacBook to its full extent yet (I will be video editing/music making soon) and will check again on the SSD situation but as of now, with my light usage of web browsing and email this usage doesn’t seem too bad.
That being said , I do have 20-30GB of writes each day if checked via activity monitor, which are still high compared to previous MacBooks.
Oh and I haven’t updated to macOS 11.4 yet, I want to wait a bit before jumping to it, as I’m still hearing some stuff about increased RAM consumption.
Current macOS 11.2.3 (the one it came with).

11.4 is much better because it actually uses your available memory unlike before where instead of using available physical RAM its just used swap.

Having to use swap increase writes.

 

[jdb8167]

Okay so divide it by 512 even if my MacBook has 256GB of memory. Thanks for clarifying.

I should add that this is 0.58TB in 23 days, MacBook Pro M1 256GB. Admittedly, I have not used my MacBook to its full extent yet (I will be video editing/music making soon) and will check again on the SSD situation but as of now, with my light usage of web browsing and email this usage doesn’t seem too bad.
That being said , I do have 20-30GB of writes each day if checked via activity monitor, which are still high compared to previous MacBooks.
Oh and I haven’t updated to macOS 11.4 yet, I want to wait a bit before jumping to it, as I’m still hearing some stuff about increased RAM consumption.
Current macOS 11.2.3 (the one it came with).

That's about 10 TB/year. The disk is likely rated for about 1600 TBW. Don't worry about it.

 

[jordysak]

11.4 is much better because it actually uses your available memory unlike before where instead of using available physical RAM its just used swap.

Having to use swap increase writes.

Okay, I guess I understand what you mean however I would worry this could be a concern on a long term basis for people with MacBooks on 8GB RAM. As of now, there are many youtubers claiming they can edit videos fine and smoothly on 8GB , hence why they often recommend the 8GB over the 16GB in order to save money, as the performance difference seems null or not significant. This was the case until now.
Now that the 11.4 has been released and people are noticing increased RAM usage, I would wanna see if the same performance as before is achievable on the 8GBs , hence showing again that there is little to no difference between the 8GBs and 16GBs. My guess is that with 11.4, please don’t take my words too seriously as I’m in no way an expert on the topic, but my guess is that if macOS 11.4 does indeed increase memory usage, then 8GB would not be enough to do certain tasks that until now were doable without any issues; and the difference between 8GB and 16GB would be more noticeable now.

 

[jordysak]

That's about 10 TB/year. The disk is likely rated for about 1600 TBW. Don't worry about it.

That’s actually a massive number; is that 1600TBW lifespan for all SSDs? Because as I said, mine is 256GB.

 

[jdb8167]

That’s actually a massive number; is that 1600TBW lifespan for all SSDs? Because as I said, mine is 256GB.

TBW is TeraBytesWritten and is a standard measure of how long an SSD will likely last. In the log, it is related to Percentage Used. We don't know precisely what Apple thinks the TBW on the M1 drives are but from various reports on 256 GB devices, it seems to be about 1600 TBW. Even if it is half that, you are good for decades at the rate you are currently writing to SSD. Obviously if you do more intensive things your writes will go up but you aren't in the category of people who were seeing a TB a day written. Those problems mostly seem solved with Big Sur 11.4.

 

[jordysak]

TBW is TeraBytesWritten and is a standard measure of how long an SSD will likely last. In the log, it is related to Percentage Used. We don't know precisely what Apple thinks the TBW on the M1 drives are but from various reports on 256 GB devices, it seems to be about 1600 TBW. Even if it is half that, you are good for decades at the rate you are currently writing to SSD. Obviously if you do more intensive things your writes will go up but you aren't in the category of people who were seeing a TB a day written. Those problems mostly seem solved with Big Sur 11.4.

Glad to hear so, thank you for explaining this.

 

[Kung gu]

That’s actually a massive number; is that 1600TBW lifespan for all SSDs? Because as I said, mine is 256GB.

The TBW rate will be higher for larger capacity drives, for example a 1TB SSD will have 4800-5000TBW.

 

[Kung gu]

Okay, I guess I understand what you mean however I would worry this could be a concern on a long term basis for people with MacBooks on 8GB RAM. As of now, there are many youtubers claiming they can edit videos fine and smoothly on 8GB , hence why they often recommend the 8GB over the 16GB in order to save money, as the performance difference seems null or not significant. This was the case until now.
Now that the 11.4 has been released and people are noticing increased RAM usage, I would wanna see if the same performance as before is achievable on the 8GBs , hence showing again that there is little to no difference between the 8GBs and 16GBs. My guess is that with 11.4, please don’t take my words too seriously as I’m in no way an expert on the topic, but my guess is that if macOS 11.4 does indeed increase memory usage, then 8GB would not be enough to do certain tasks that until now were doable without any issues; and the difference between 8GB and 16GB would be more noticeable now.

If 8GB is not enough then macOS will use swap. But in 11.4 it fill up the RAM before using swap. I mean why even have RAM if the OS is not going to use it?