I've seen all the news around the M1 Mac writing the SSD excessively and I also have very high write counts on my SSD already.

I do know SSDs do have a spare capacity they can assign to blocks once an original block is damaged. But this is only a few blocks as far as I know - is there any possibility to for example Mae the official capacity of the SSD smaller by 10GB and give those blocks as additional spares to the controller so it can prolong the live of the SSD a bit longer once blocks start dying?

Or how would you go about securing the SSD Life? Is it a possibility to shrink the partition and zero out the rest of the drive so the controller can use these blocks? Would this include a firmware update of the ssd controller? I'm a bit lost about where to start with this.


SSDs just don't work like that.
Formatting & partitioning aren't placed in 'zones' like on an HD. The sectors/cells that the drive keeps as spares aren't even accessible to the OS, only to the drive's internal firmware. SSDs 'spray' data right across the usable sectors using complex algorithms really only known to the drive itself to prevent excessive wear.

The way to ensure an SSDs life is to keep a lot of free space on it. The smaller the drive, the larger the percentage. 10-15% minimum free on large drives; teeny ones, 128GB & 256GB, I'd keep a minimum of 25-35GB free.

  • But wouldn't that mean that shrinking the main partition would help then, because that would limit the maximum used space. So for example I got my 512GB SSD, and shrink the main partition down to let's say 470-480GB thus always reserving that space as free space on the SSD that can not be used at any time? – bardiir Apr 8 at 17:43
  • It would give you a warning [or hard crash] sooner but wouldn't make any other practical difference. To do it, you'd have to actually shrink the container not the partition. Partitions on APFS don't have a fixed size, but the container does. – Tetsujin Apr 8 at 17:45
  • This is why I would have liked to give up some space towards the headroom that the OS can not see instead of just having it free - because the drive then would have a lot more spare sectors to replace in the first place before there is a hard fail when the controller cannot maintain the amount of space on the drive anymore. – bardiir Apr 8 at 17:48
  • tbh, it's the same whether you shrink the container or just don't ever fill up the drive. The difference is really only cosmetic. – Tetsujin Apr 8 at 18:13
  • Yes but over-provisioning should probably be different because more of the device can die before it ends in an unrecoverable error for the controller, the question is mostly can it be over provisioned somehow. – bardiir Apr 8 at 19:25

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