Can't Restart Datameer: Read-only File System

Problem

Datameer started producing 404 errors for many pages. Upon attempting to restart the conductor, it would not start and the following error was seen in the jvm-stdout.log file:

Read-only file system

Cause

An Operating System level event occurred that damaged the disk filesystem where Datameer resides. This caused the Operating System to dismount the filesystem and re-mount is as read-only leading to the inability for the Datameer conductor to find the files on disk or perform cleanup of the temporary folders when attempting to restart.

Solution

To resolve this issue, the filesystem needs to be dismounted using the UMOUNT command, then FSCK needs to be run in order to correct the disk errors. Once the filesystem has been repaired, it can be remounted using MOUNT, and finally the Datameer conductor restarted.