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I have a spare SSD which I keep at home in case one breaks. I've seen articles about SSDs losing data over time even if they are not being used, but can unused/empty SSDs degrade over time too? (and is there a difference if the SSD is plugged in and powered on or not)

I am wondering whether I should just wait for signs that an SSD is breaking before buying a new one in the future.

dippynark
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  • Are you talking about hardware failure or losing data? SSDs store data as a charge, which can reduce over time. Refreshing the data by re-writing it would probably help, but I don't know if that is possible / practical - defragmenting might be part of the solution. In terms of hardware failure yes everything fails, you can monitor SMART data but I suspect SSDs fail immediately rather than degrade in a way that can be detected in advance. – Tim Nov 16 '20 at 21:26
  • Hardware failure -- the spare drive is empty at the moment so there's no data on it to lose. The question seems silly after reading again as clearly physical things will degrade, but I guess what I am wondering is whether buying two disks and leaving the spare one unplugged until it's needed is worth it. But I guess that's not something that can be answered generally – dippynark Nov 16 '20 at 23:22
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    A spare without data could be handy, but if uptime is critical two different brands in a RAID mirror array could be more helpful than an empty drive and having to restore from backup. – Tim Nov 17 '20 at 00:08
  • Unfortunately I'm using Flatcar Linux which doesn't support proper RAID 1 on the rootfs :( (https://unix.stackexchange.com/questions/619759/what-are-the-implications-of-flatcar-linuxs-root-filesystem-raid-limitations) -- but yeah that'd be my preference – dippynark Nov 17 '20 at 09:50
  • The RAID limitations you cite seem to be regarding Linux bootloaders. Which while annoying, can be recreated relatively easily upon failure. You didn't mention this in your initial question, I thought you were referring to external solid state media you were backing up with and shipping off site. – John Mahowald Nov 17 '20 at 14:14
  • I think I felt based on the response in the link that I understood the limitations there, but this question I was more just curiosity around whether the degradation of a disk when it's sitting there doing nothing and has never been used is even worth considering/worrying about. In hindsight I think there are too many specifics that determine that so yeah I should have included what I was actually trying to do – dippynark Nov 17 '20 at 19:20

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Yes, all physical things degrade.

Professional archivists, when preserving important data on digital media, regularly test that media. Possibly they have more stringent requirements than the restore objectives of your organization, but this seems like a good idea:

Read a statistical sample (3% minimum) of recorded media annually to identify and correct any loss of data. Re-copy batch if errors appear.

Solid state storage technology is new enough where it is unlikely your model has been tested for the several years it might take to wear under light stress. Reliability expectations are from a brutal write workload with temperature extremes, and extrapolating from there. See for example JEDEC SSD test procedures.

In practice, replace media when any of these happen: errors reading from it, self health metrics look bad, or nearing end of warranty. Presumably, the data is more valuable than any one drive it happens to be stored on this year.

John Mahowald
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