I don't know, but it is well within the write speed capability of the internal drive, so not a physical impossibility.
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ssd swap - high usage of Terabytes Written
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That is weird. Any idea or even theories on what caused it? The graph is somewhat linear except for that piece of strangeness.
I also had an event that wrote 1 TB overnight so that figure of 1.3PB is perhaps possible. Using simple average rates is not the way this effect works.
So far for me, by following the tips at the start of this thread and a few others I've discovered I am at 77TB for a MBA M1, 256/8 at 14 months in my hands. No idea what it was when I bought it 2nd hand in Jan 2021 but a lookup said manufactured Nov 2020.
Up to date chart shows a nice smooth plot.
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As I have said in subsequent posts I have no idea what caused it and did not notice it happening at the time.
The data is coming from Apple APIs via the SoC’s SSD controller. There is no third party interpretation happening here.
One thing to keep in mind is that Apple might be showing a more accurate Percentage Remaining than other vendors because they don’t warranty based on that. They just have their standard warranty and AppleCare.
Exactly, and thats why I tend to believe the info that this is a reporting bug that triggers under certain esoteric conditions.
120 GB writes an hour equates to 1.67% workload for the ssd capabilities. It was well possible left unnoticed because it shouldn't cause lags.
Math: 1 hour = 60 minutes = 3600 seconds. SSD let's say writes 2000MB/S, meaning that 7.2 million MB writes possible under hour. 120GB/7.2 million MB = 1.67%.
Highly unlikely but it can’t be ruled out.
And why is a reporting bug more likely than a runaway SSD write bug?
My MBA has averaged 650GB/day over 18 months. It's a 1TB/16GB machine. I keep hundreds of tabs open. I see swap being used. On an 8GB machine, many multiple times that wouldn't be unreasonable.
DriveDX reports 340TB total writes, 3B write commands, about 88% of SSD life left.
So about 40-50GB/hour of swap usage (about 15-20 seconds an hour at max throughput). That sounds about right actually.
If you're worried such things, best to equip with more memory or a larger SSD. At 2TB it'd be 14+ years left, at 256GB, less than 2. I've got about 7-8 years left at this rate. I'm not worried about it.
DriveDX reports 340TB total writes, 3B write commands, about 88% of SSD life left.
So about 40-50GB/hour of swap usage (about 15-20 seconds an hour at max throughput). That sounds about right actually.
If you're worried such things, best to equip with more memory or a larger SSD. At 2TB it'd be 14+ years left, at 256GB, less than 2. I've got about 7-8 years left at this rate. I'm not worried about it.
120GB an hour is high, but not out of the question if you keep a lot of applications and tabs open on a 8GB machine.
Across a 10 hour day, this is less than 10 minutes of write activity totalling ~1TB. One rewrite a day for a 1TB drive.
The 8GB/256GB machine owner undersized the machine for their usage pattern.
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Lol not everyone can have the luxury to chose a higher spec Mac.
People are bringing this issue out of proportion.
Ive been monitoring disk usage on my base M1 Air and while the numbers are crazy I trust its working as intended and it's serving me exceptionally well.
Currently I have 35TBW at 2% of wear level, which means Apple rated the 256gb SSD for ~1.7 petabytes of writes. I'm a web developer and on intense days I'm averaging ~1TBW while ~500GBW on normal days, so even if I keep this usage every single day of the year it will be almost 5 years before I reach the 100% mark which probably includes a very comfortable safe margin, I can see it lasting twice that mark.
In my opinion, these machines will be obsolete before the SSD dies from wear, if ever. Otherwise it won't be long before Apple announces a repair program to replace millions of Macs, including desktops like the 24" iMac and Mac mini.
I know some people wear level is very high because of the ssd trashing issue that was only fixed in 11.4 (luckily I got my Mac already on Monterey) but I still believe it won't affect longevity.
While true there is the issue of what is the planned use of said machine. If you are planning on development work IMHO going below 16 GB/512 GB is just asking for issues. $1,099.00 for a Mini is well within reason and the extra $449 for the Air is money well spent.
It isn't just the OS but people pushing the machine to levels that are way beyond what the RAM can provide, having programs that need Rosetta 2, or using Chrome. I agree with you but it is clear there are programs that are overwriting to the SSD.
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There's no such things as beyond what ram can provide lol the machine works great. Using swap cache is not a sin, that's how macOS works, it's a tool, when someone with a 64gb M1 Max open multiple heavy apps and load heavy assets to work? It's gonna use just as much swap as my M1 Air is using with my dev tools and browsers running, it's meant to be used to it's limits, the moment you feel you're being slowed down you'll know you need more. Implying the base M1 Macs are meant for light browsing only is a insult to the top tier engineers at Apple.
If you're worried about SSD wear, spend a little on the next tier of memory or storage. It's designed like that.
Base M1 Macs are meant for light productivity and browsing.
Because we don't see these SSDs failing en masse. M1 Macs have been out for almost two years now, and a lot of folks own the base 8GB/256GB model. If high SSD writes were a common thing we would start seeing Airs failing left and right about half a year ago. But it did not happen.
I don't know, my gut feeling makes me very sceptical. Swap is one thing, but constant swapping out will only occur when you continuously allocate new memory and push inactive pages out. You need to be in a memory starved situation (to defeat memory compression) and continuously cycle through tabs, repeatedly opening and closing them. Let's say a browser tab uses around 100MB of private (not shared) memory pages, which is already on the high side. To reach 500GB/day in 10 hours (I suppose you are not sitting on your computer 24/7) you'd need to consistently and completely swap out around nine browser tabs per minute. That's a LOT of browser tab cycling.
I mean, I also have hundreds of tabs open, but most of the time they just sit there. I am not cycling though them over and over again. But who knows, maybe there are people who really do it.
What does your vm_stat say (run it in terminal)? I am particularly interested in swapout count.
Could you please give me some hints about my vm_stat:
Mach Virtual Memory Statistics: (page size of 16384 bytes)
Pages free: 4397.
Pages active: 93787.
Pages inactive: 86436.
Pages speculative: 5809.
Pages throttled: 0.
Pages wired down: 82780.
Pages purgeable: 71.
"Translation faults": 1669026366.
Pages copy-on-write: 11452660.
Pages zero filled: 314751502.
Pages reactivated: 500168653.
Pages purged: 21095066.
File-backed pages: 70311.
Anonymous pages: 115721.
Pages stored in compressor: 596321.
Pages occupied by compressor: 215216.
Decompressions: 644140773.
Compressions: 692973897.
Pageins: 38067617.
Pageouts: 811101.
Swapins: 72779559.
Swapouts: 73496206.
Pages free: 4397.
Pages active: 93787.
Pages inactive: 86436.
Pages speculative: 5809.
Pages throttled: 0.
Pages wired down: 82780.
Pages purgeable: 71.
"Translation faults": 1669026366.
Pages copy-on-write: 11452660.
Pages zero filled: 314751502.
Pages reactivated: 500168653.
Pages purged: 21095066.
File-backed pages: 70311.
Anonymous pages: 115721.
Pages stored in compressor: 596321.
Pages occupied by compressor: 215216.
Decompressions: 644140773.
Compressions: 692973897.
Pageins: 38067617.
Pageouts: 811101.
Swapins: 72779559.
Swapouts: 73496206.
If I interpret this correctly, around 1TB of app memory has been written to the swap in the current session (73496206 pages of 16KB each). However, the real value could be much smaller since macOS is probably only swapping compressed pages.
When did you last reboot or shut down your computer?
Constant swapping does not require continuous allocation, or tab cycling. The root cause always boils down to the working set (that is, the set of pages which are frequently being accessed) being substantially larger than the available physical memory.
I partially blame Youtubers for people under specking their Macs, with videos like 8GB is the new 16 GB 
Just because it works “ok” does not mean it is the way to go.
Also apple should just have done min 16 GB.
8GB is about as bad as putting 256 GB ssd in a computer, unless you do only web browsing.
Just because it works “ok” does not mean it is the way to go.
Also apple should just have done min 16 GB.
8GB is about as bad as putting 256 GB ssd in a computer, unless you do only web browsing.
Browser tabs in the inactive are usually excluded, or at least largely excluded, from the working set, are they not?
I am familiar with how virtual memory works. That’s why I write what I did. Inactive tabs consume very little active memory, if at all. I don’t see a reason why high amount if browser tabs should result in excessive swapping on a modern browser.
I have had a couple of 32GB Macs for the last few years and in my experience *most* of my RAM usage comes from web browsing. I'm nearly always using a significant amount of compressed memory and some swap, and often have "yellow" memory pressure (due I think to high usage of compressed memory, rather than constant swapping).I partially blame Youtubers for people under specking their Macs, with videos like 8GB is the new 16 GB
Just because it works “ok” does not mean it is the way to go.
Also apple should just have done min 16 GB.
8GB is about as bad as putting 256 GB ssd in a computer, unless you do only web browsing.
I don't think "only web browsing" means you need a low spec machine. Web sites running full-featured web-apps can use a lot of computing resources, equal to many desktop apps.
To provide a reference, here is my vm_stat after nearly 2 days of uptime:
Code:
Mach Virtual Memory Statistics: (page size of 16384 bytes)
Pages free: 6013.
Pages active: 846388.
Pages inactive: 807221.
Pages speculative: 36494.
Pages throttled: 0.
Pages wired down: 154665.
Pages purgeable: 15069.
"Translation faults": 400321787.
Pages copy-on-write: 6903167.
Pages zero filled: 151347241.
Pages reactivated: 1425949.
Pages purged: 1331405.
File-backed pages: 629193.
Anonymous pages: 1060910.
Pages stored in compressor: 501711.
Pages occupied by compressor: 192899.
Decompressions: 321359.
Compressions: 1005651.
Pageins: 2460036.
Pageouts: 37586.
Swapins: 4416.
Swapouts: 4576.The swap outs are about 75MB or 71.5 MiB,
However, the data written since reboot is 1000 times more (71GB).
I haven't done any large file copies, so that it quite a discrepancy!
What is the difference between Pageouts/ins and Swapouts/ins?
Seems like I still have a long way to go with my 2016 MacBook Pro, especially since it will get used much less when the Mac Studio finally arrives. I've been using it heavily every day for over 5 years now, with a lot of file transferring:
Data Units Read: 109,240,455 [55.9 TB]
Data Units Written: 83,995,248 [43.0 TB]
That's pretty low usage. I had over 4 times your write figure (c. 180TB) written over 2 years with my late-2019 MBP.
I wasn't very kind to it in terms of memory usage, and didn't try to "save" memory by closing apps & browser tabs to keep my swap usage low. High swap leads to a lot more disk writes, I have found.