I had an issue today where a Linux VM’s file system was read only after a SAN issue. When a Linux server like Ubuntu looses access to its disks, the file system can go into read only to protect it from corruption.
To resolve this you will need to run the following command:
sudo fsck -As
FSCK is the file system check utility in Linux, and the A switch will run through the FSTab to check all file systems in one run. The s switch serializes the FSCK operations, which is a good idea if you are doing multiple file systems.
You may be promoted to fix the file system, I selected yes as there may have been some corruption.
Once completed, I performed a reboot. Once the server rebooted and the file system repaired, there servers file system was back in read write mode.