Why does linux filesystem go into read mode?

Question

linux

Please tell me why FS linux goes into read mode, although no manipulations with the server have been carried out!? And the second question is how to avoid such a situation?

Answer 1

in fstab it is written error=remount-ro
most likely disk errors. what does dmesg say?

Answer 2

Most likely the disk has fallen.
See Smart disk (smartmontools, gsmartcontrol).

Answer 3

This often happens to me on different devices, the following command helps
mount -o, remount, rw /