ssd swap - high usage of Terabytes Written

[thadoggfather]

so the issue is resolved for sure with 11.4?

I think over like 100 days, it was only a few TB written and like 2 and 4 read...

My SSD lives to see another day on my base M1 Air

 

[TheSynchronizer]

11.0 -> 11.4
800GB / day -> 25-50 GB a day
same heavy use, different browser

 

[Homy]

I am trying to leave at least 15 to 20 Gb of space by putting as much as I can on my NAS. Currently I have 21 Gb free after another round of cleanup with disk Inventory X.
But have you ever installed Xcode?

No, I don't use Xcode but it seems that you need more than 15 GB free space. Does Xcode use the SSD for temporary files? I noticed you also have only 8 GB. How much RAM does Xcode use? Maybe that's another reason for large swap usage. Maybe Xcode needs more than 8 GB RAM and has to write a lot to the SSD. I have a 2011 iMac 21.5" with 500 GB HDD and I try to leave 40-50 GB free. Before when I only had 20-25 GB free space my iMac got slow.

 

[Mc0]

Mine's good as well.

MBP 2017 13 8GB RAM
11.3 - erratic writes between 50 - 75GB per day
11.4 - Avg 35GB per day

M1 MBP 16GB RAM
11.3 - erratic writes 60 - 120GB per day
11.4 - Avg 30 - 35 GB per day

3 browsers open (6 - 10 tabs per browser) for web dev works, VS code, DB2, Github, MAMP Pro, Slack, Webex Teams, Spotify, Mail, Excel

 

[helloapple1]

Is it Reads or Writes that are more important metric?

 

[strawbale]

About to bite the M1 bullet - will be a Mac Mini with 16GB RAM, but haven't made up my mind on SSD size yet. Currently using a 8/256 MM2018 with no problems and still 160GB available (keeping photos and music on an rxternal disk). Now with 11.4 looking to have solved the high TBW issue, is there any good reason for me to go beyond 256GB?

 

[thenewperson]

About to bite the M1 bullet - will be a Mac Mini with 16GB RAM, but haven't made up my mind on SSD size yet. Currently using a 8/256 MM2018 with no problems and still 160GB available (keeping photos and music on an rxternal disk). Now with 11.4 looking to have solved the high TBW issue, is there any good reason for me to go beyond 256GB?

No. If 256GB is enough storage for you don’t pay Apple’s prices. External storage as expansion is at least an option that exists.

 

[leman]

2 Questions please:

1. What is a healthy, average number per hour based on typical usage? Is it around 5GB/hour?
2. What are some of the worst per hour figures we have seen here? I just want to see for comparison

I don't think there is a "healthy" average number simply because it will depend on how you use the machine. Probably the more useful way to think about it is in terms of how much writes your disk can sustain. We can reasonably assume that these Macs have an endurance of around 500-700TBW (which is much higher than your average consumer SSD). So check how much writes were done to your SSD and compare that to the above number. If you had 150TB write in just a couple of months, that is definitely to high, as it means the drive is unlikely to survive a year.

 

[leons]

Looking in activity monitor are we looking at the Data Read or Data Written number?

Date Written/Writes

 

[leons]

Welcome to the ‘stopped using Safari’ club .

If I kept using Safari to this day ever since I noticed heavy SSD writes some time in December, I’d probably be on atleast 400TB written and counting. But I was lucky enough to notice the issue quite early and I switched from Safari to any other browser, and it’s honestly the biggest reason why my SSD wrote 23.1TB between November 26th and December 30th, and now since then it’s only written 2TB in 6 months and as of now I’m on 25.1 TB.

I think if you take any steps needed to circumvent the issue on your part now, you’d still have a macbook that would last for a very long time. E.g. if you were to write ~4TB a year like I do now, or even something larger like 20TB a year, then your mac would likely still last for more than 24 years, and maybe even 50+ years (these SSDs seem to be rated at around 1400TBW according to the percentage used value).

Currently I use Firefox with a few tweaks and modifications, which I’ve even managed to make look like Safari - I browse with 100s+ of tabs all the time with no issues as a computer science student. View attachment 1782903


I highly recommend it, and if you want I can point you to useful tweaks and modifications that reduce swap writes even further. Other good browser choices that I know of are Brave, Edge and Vivaldi.

It’s not too late!

Hi! Looks like you switched from Brave to Firefox? What were your reasons?

 

[k-hawinkler]

I don't think there is a "healthy" average number simply because it will depend on how you use the machine. Probably the more useful way to think about it is in terms of how much writes your disk can sustain. We can reasonably assume that these Macs have an endurance of around 500-700TBW (which is much higher than your average consumer SSD). So check how much writes were done to your SSD and compare that to the above number. If you had 150TB write in just a couple of months, that is definitely to high, as it means the drive is unlikely to survive a year.

I prefer to think in terms of writes per cell, then multiply that with the capacity of the SSD.
For example assuming the Toshiba number of 3,000 writes per cell, and an SSD capacity of 1 TB, yields 3,000 TBW as an expected number to go by.
So a 256 GB SSD capacity would give 3,000/4 = 750 TBW.
And so on, a 128 GB SSD capacity would give 750/2 = 375 TBW.
If you prefer a different writes per cell number use that one instead.

In about 4.5 months the 2 TB SSD in my M1 Mac mini has used up 6.2 TBW.
Well, nothing to worry about.

 

[jdb8167]

Is it Reads or Writes that are more important metric?

Writes. Specifically "Data Units Written" which is translated by the tools as TBW (TeraBytesWritten).

 

[TheSynchronizer]

Hi! Looks like you switched from Brave to Firefox? What were your reasons?

Unfortunately it seems like one of my uni’s websites would cause memory leaks quite regularly when using Brave - the memory usage would get high with 31+ processes running in activity monitor and not get freed. This doesn’t happen to me on firefox and it’s probably not a widespread issue

As a bonus I was able to tweak firefox for even lower memory usage by reducing the number of ‘Content Process Limit’. But by all means brave is great and I have no issues with it otherwise

 

[wirtandi]

I would say 5GB/hour is quite healthy - let's say 50GB/day if you are working for 10 hours per day, or 1-1.5TB per month. You would comfortably exceed the likely usable life of the machine. I personally want my gear to last at least 10 years, even if I had gifted or sold it before that time.

Some people have reported over 1TB of writes per day, so around 100GB/hour for a full working day.

Yes I agree. I think even 10GB/hour or so is still quite ok.

Well, 1TB per day is quite crazy 😆

 

[wirtandi]

Btw, I remember that the "data written" in activity monitor records ALL data. This means when you transfer files to and from an external SSD, time machine backups, etc. will all be counted towards the "data written". On the other hand, the smartctl -a disk0 (data units written) only records the data that is actually written to the SSD, which means this is more accurate and this is what I should be looking at.

Am I correct? Basically I need to be keeping an eye on the "data units written" in smartctl as opposed to the "data written" in activity monitor?

 

[jdb8167]

Am I correct? Basically I need to be keeping an eye on the "data units written" in smartctl as opposed to the "data written" in activity monitor?

Correct. Activity Monitor is useful as a quick look to see if your current workflow is causing problems but for long term monitoring you want the SMART data from smartmontools.

 

[Maximara]

I am trying to leave at least 15 to 20 Gb of space by putting as much as I can on my NAS. Currently I have 21 Gb free after another round of cleanup with disk Inventory X.
But have you ever installed Xcode?

I have ...on my external 2 TB HD (which I boot from) and while Xcode will use a lot of RAM you can still lessen the impact by having file saves off the SSD at much as possible (platter drive are cheap and aren't that slow...generally).

 

[sneeks]

I’ve owned my Mac Mini 16/256 for 3 weeks now and so far all looking good. When it arrived it had 345gb data written and today it has 835gb, a 490gb increase over 3 weeks. Also I left the Mac Mini on for 17 hours and total GB written, which includes to a external drive, is 8.32gb. During this time I did some photo editing in Lightroom, web browsing and YouTube viewing. I’d like to think with these figures my 256gb drive will last many years.

 

[seadragon]

Hi everyone... I just got my Apple refurbished M1 Mac mini 16/2TB a couple of days ago. It was manufactured in early February 2021. It came with 11.2.3 installed which I immediately updated to 11.4 after initial setup. I've installed Logic and FCP so far. I just ran DriveDx which shows the following:

Does this look good? Would DriveDx show any abnormal usage?

Thanks for your feedback.

 

[k-hawinkler]

This looks very good.
Indeed DriveDx would show that.
Your SSD has barely been used.

I bought my M1 Mac mini 16GB/2TB new in January.
My SSD is at 6.2 TB written according to DriveDx.

 

[rob984]

I’ve owned my Mac Mini 16/256 for 3 weeks now and so far all looking good. When it arrived it had 345gb data written and today it has 835gb, a 490gb increase over 3 weeks. Also I left the Mac Mini on for 17 hours and total GB written, which includes to a external drive, is 8.32gb. During this time I did some photo editing in Lightroom, web browsing and YouTube viewing. I’d like to think with these figures my 256gb drive will last many years.

That was new or refurbished? Because when I bought mine in the store, it already had around 300GB written.

 

[k-hawinkler]

300 or 345 GB written is brand new.
I didn’t think that low was possible.

My 7 year old “trashcan” late 2013 Mac Pro has about 70 TB total written on it.
So, that’s about 10 TB per year average.

My new M1 Mac mini right now is on a course of about 15 TB written per year.
Either computer is in great shape.

What seems important is to not fill up your SSD to more than about 75 or 80%.
Then the SSD should not lose storage cells prematurely.

 

[sneeks]

That was new or refurbished? Because when I bought mine in the store, it already had around 300GB written.

It is refurbished but I don’t think it was ever used, I had a 8gb version which I swapped for this and that had 3.5TB written when first used by me.

 

[rob984]

thanks! I guess that's from testing and from installing OS.

 

[kubilaydem]

Hi !

How about safari after the update? Is it ok to use now?