[Discuss] Help with I/O errors on RAID array?

[markw at mohawksoft.com]

Interesting. What file system are you using? XFS? EXT4?
Have you looked at /var/log/messages and/or dmesg to see more details
about the error?

I wonder if there is an error in the file system.

> I wrote about errors on my RAID-1 array:
>>> $ cat myfile
>>> cat: myfile: Input/output error
>>>
>>>...how to figure out which (if any) of the two SSDs is faulty?
>
> On October 13, 2025, Rich Pieri wrote:
>>Break the mirror and see which one still faults.
>
> I tried to do this, and weirdly, both drives still faulted on the same
> file.  Here's what I did:
>
> 1. Boot on a rescue CD. (Since the array is my root partition.)
>
> 2. Create a RAID-1 array containing just one of the SSDs:
>
>   $ sudo mdadm --assemble --readonly /dev/md0 /dev/nvme0n1p1 --run
>
> 3. Mount the array and try the same "cat" command. It produces an
> input/output error as before.
>
> 4. Stop the array:
>
>   $ sudo mdadm --stop /dev/md0
>
> 5. Repeat the process for the other SSD, /dev/nvme1n1p1. Same result!
>
> When *both* drives from an array produce the same disk error
> independently, where does the actual problem lies?
>
> Or did I do something wrong?
>
> Thank you again,
> Dan
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