{"id":31740,"date":"2021-02-26T17:05:14","date_gmt":"2021-02-26T22:05:14","guid":{"rendered":"https:\/\/mjtsai.com\/blog\/?p=31740"},"modified":"2021-05-25T16:00:35","modified_gmt":"2021-05-25T20:00:35","slug":"excessive-mac-ssd-wear","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2021\/02\/26\/excessive-mac-ssd-wear\/","title":{"rendered":"Excessive Mac SSD Wear"},"content":{"rendered":"

Hartley Charlton<\/a> (Hacker News<\/a>):<\/p>\n

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Across Twitter and the MacRumors<\/em> forums<\/a>, users are reporting that M1 Macs are experiencing extremely high drive writes over a short space of time. In what appear to be the most severe cases, M1 Macs are said to be<\/a> consuming as much as 10 to 13 percent of the maximum warrantable total bytes written (TBW) value of its SSD.<\/p>\n

[…]<\/p>\n

It is not known how widespread the TBW issue is, but reports<\/a> of strange SSD behavior are also now emerging from users with Intel-based Macs, suggesting that the TBW issue may not be exclusive to M1 Macs.<\/p>\n<\/blockquote>\n\n

Dan Moren<\/a>:<\/p>\n

I ran the command-line tests on my own M1 MacBook Air versus my 2017 iMac<\/a>, and it certainly did seem as though some of the numbers on the Air were higher than they should be, given the amount of relative use.<\/p><\/blockquote>\n\n

The numbers for older Macs reported on Accidental Tech Podcast<\/a> also seem higher than I would have expected.<\/p>\n\n

Update (2021-03-11): Ben Lovejoy<\/a> (tweet<\/a>):<\/p>\n

Second, he says than SSD vendors have to be very conservative in their wear ratings, as it leaves them on the hook for warranty claims if a drive fails before reaching its rated wear limit. In practice, SSDs can commonly cope with four times as much wear.<\/p><\/blockquote>\n

Regardless, I think we need to figure out why macOS is writing (or reporting that it’s writing) so much more data than intuitively seems reasonable. And this is not an issue limited to M1 Macs.<\/p>\n\n

Update (2021-05-25): Hector Martin<\/a>:<\/p>\n

Update on the macOS SSD thrashing issue: It seems the issue is fixed in 11.4. Feel free to try the betas if you’re adventurous, or wait for the final release.<\/p>

It’s going to be interesting diffing the XNU kernel source once it drops and seeing what the bug was…<\/p><\/blockquote>\n\n

Previously:<\/p>\n