Re: SD card corruption

Hi,

> On 13 Jul 2023, at 16:33, mike tancsa <mike@sentex.net> wrote:
> 
> TL;DR. We get batches of cards that suddenly fail with SD card wide file corruption out of the blue.
> 
> 
> A little background.  We have APUs (PCEngines) in the field that work REALLY well for reliability.  However, the odd time that things go south, its due to SD cards.  I had a couple of devices last week fail after about a year and when I got them back both had hundreds of fsck errors. These are devices that stay mounted Read Only so there are no writes to them. Even on the second partition of the nanobsd image which was never mounted had many fsck errors.  Normally we use SanDisk but had to switch to some PNY due to supply chain issues.  The PNY seem to be more failure prone than the SanDisk, but we do get the odd SanDisk too with the same pathology.
> 
> Once I get the bad SD card back, I can newfs it and all is fine. e.g. I can fill the disk with 16GB of /dev/urandom files and the hashes all match over time.
> 
> Is it just bad hardware / bad luck that is causing these seemingly catastrophic failures or are there things that should be done in the field to extend the life of SD cards ?

What’s the environment like? SD cards really don’t like being run hot for instance. Are there radios or other electrical noise nearby?

> Is there any way to predict these failures in advance ?
> 
> If I newfs -E (does the -E make a difference?) the unused partition and then re-write it with the live image and then boot to the new partition, does that buy my any longevity ?
> 
>     ---Mike
> 
> 

--
Bob Bishop
rb@gid.co.uk