[GTALUG] nvme SSD: critical medium error, dev nvme0n1

[Stewart C. Russell]

On 2019-08-06 3:30 p.m., D. Hugh Redelmeier via talk wrote:
> 
> |     unsafe_shutdowns                    : 10

Oddly, there hadn't been an unsafe shutdown for ages. While I do have a
UPS, I've sometimes had the machine hard lock with no way to get it to
do anything. Maybe those are counted that way, but there was no disk
activity when I did the "unsafe" shutdowns.

> There's a chance that this number explains your bad data.  

> |     media_errors                        : 803
> |     num_err_log_entries                 : 844
> 
> You can read this log (using smartctl).

Not on NVME, and seemingly the Intel-specific drivers that this device
uses only give summary results. `nvme smart-log-add` does nothing.

These numbers haven't changed any on subsequent remounts.

> | * a decent brand to replace it with. I'm likely okay with a SATA SSD.
> …
> You want an NVMe drive, right?

I ended up with a 1 TB WD Blue SSD for $140 + tax. Not NVME, but fast
enough. Because this machine (though only 2-ish years old) had some
legacy OS boot cruft on it, doing a clean Ubuntu install means that boot
time is around 5 seconds.

> The more bits per cell, 
> - the more bits you can fit on a flash chip
> - the slower the operations
> - the sooner the cell will wear out.

I just wish the old drive had the smarts to remap bad sectors. There
were a couple of files that *always* caused kernel errors, but enough
space that files could be moved/made lost+found. What really annoyed me
was that fsck would show clean, but these files still existed with errors.

cheers,
 Stewart