Diagnosing filesystem errors

Unlike earlier chapters where end users were reporting the issue to us, this time around we have found an issue for ourselves. While performing some daily tasks on the database server we attempted to create a database backup and received the following error:

[db]# mysqldump wordpress > /data/backups/wordpress.sql
-bash: /data/backups/wordpress.sql: Read-only file system

This error is interesting because it is not necessarily from the mysqldump command, but rather from the bash redirect that writes to the /data/backups/wordpress.sql file.

If we look at the error it is very specific, the filesystem we were attempting to write the backup to, is Read-only. What does Read-only mean?

Read-only filesystems

When defining and mounting filesystems on Linux you have many options, but there are two options that define the filesystem's accessibility best. Those two options are rw for read and write, and ro for read-only. When a filesystem is mounted with the read and write...