A power off, not shutting down correctly, could cause it, Does this happen every time you re-boot, ?
But there are many other things or events that could cause it, why have you not looked at the logs, to try to see if they show anything ?
There are many things in your posts that are not making sense to me :
So, if some unit fails (or does not boot), we need to take a truck and drive almost 4 hours for maintenance.
and
That Debian is installed on a embedded computer, that will be installed in the field ---snip--
"will be installed in the field", implies it has not yet been installed in the field, yet above , the OP say they have to take a truck, and drive 4 hours, for maintenance,
The system transmits data to our cloud servers using 3G connection, so there is no way to connect to them remotelly.
That seems just plain foolish, if it is "transmitting" to some kind of cloud server, why don't you use ssh to access, it ?
To have a remote system, and not even have ssh access to it, just does not make sense to me,
How can I check my disk integrity?
There are many tools available to do that, why have you not done any searches, and tried some ?
Are you really the administrator of this system ? or just the "owner",It sounds to me like you need to find a qualified person / tech to help you set up this remote system, and administer it for you, if you work with them, they can show you how and what they do, also keep notes, so that once you understand the
procedures, you can do these things, perform maintenance, trouble shoot,etc...
If there is any doubt that the drive is good, then by all means replace it with a good one,
I know how to recover from the error and I know what this error is about.
This makes the least amount of sense, if you know what the error is about, WHY are you asking us ?
You have not provided 1 shred of clues, error logs, etc, and there seem to be a lot of details about this you are not telling us,... I can't help but wonder, why on earth you are using a unsupported, out of date version of Debian this, especially since it is in a remote location, and not easy to access physically,...
It seems like it would be essential to use a reliable, supported Debian version,
or maybe even another OS, I do understand some of the problems with the newer versions of Debian, and as much as I like to support Debian, and do think it is a good OS, if you feel you must use Debian 7 (wheezy), it might be better to look into some other options, that are current, maintained, and supported by the developers.
I have 1 Debian 7 server, and actually know of some sites that are still using Debian 6, (squeeze), how ever even though my server (and many others ) are
in a remote location, we do have someone actually there, on the server farm, that some one is a skilled administrator/tech, and is there to take care of the machines, and handle anything that requires some one with physical access.
Any way, Debian is reliable enough, but another think I don't understand, after your system is booted and running, Why or how does it get shutdown, or need to re-boot, I mean, it sounds rather ridicules to me the setup you have.
You have no remote access, ? Years ago I had several remote ham radio stations, 1 legal requirement for that is that one has the means to shutdown the station , in case something goes wrong and it starts transmitting unwanted signals, or something. I had it set up to where I could access, and turn off the power supply, via a radio transmission, I could also access the computer via radio transmission, of course if the power was shut off, even the computer could not be accessed,... sorry to be rambling,... any way what we need here is a lot more / better details on your system, and if you do not understand what your logs show, shows us what they have, maybe some one here will be able to see what caused the file system to get damaged, so that it is not readable,or fails to recognize its filesystem, Unknown filesystem.
Some times, just running 'fsck' manually can repair this, in fact it seems like it would be a good idea to have this "embedded" system run fsck , every time it boots,
, and check for any errors,... ok well sorry about the ToLong of a post,... Since nobody here has access to your system, it is rather difficult, if not impossible to diagnose, and tell you what is causing the errors, there are to many different things that could cause this.