Pool has encountered an uncorrectable I/O failure and has been suspended

[oraclep]

One day, the web interface arose, stopped responding and smb disappeared.
There was an error on the screen indicated in the subject of the post.
The following has been done:
1. Disabled true nas
2. Disconnected one of the drives to find out which one is not working.
3. The web interface loaded, but the pool was offline
4. Turn off true nas
5. Connected the drive.
6. Turned on the truenas and everything worked.

The question is, what could this be and is it worth worrying about?

 

[jgreco]

Welcome to the forums.

Sorry to hear you're having trouble. Please take a few moments to review the Forum Rules, conveniently linked at the top of every page in red, and pay particular attention to the section on how to formulate a useful problem report, especially including a detailed description of your hardware.

You've basically given no one anything to work with, so the responses will tend to be random guesses rather than anything useful.