Filesystem is read-only

A mounted filesystem is read-only, so anything that writes to it will fail; data already on it stays readable. Severity depends on whether the KERNEL corroborates it. If the kernel logged a remount-read-only event, the filesystem was forced read-only because it failed, usually from I/O errors, and this is critical. If only the mount options say read-only, it is reported as a warning and an observation, because that state also has entirely benign causes; an intentionally read-only bind mount, immutable infrastructure, or an operator remount. Confirm which before treating it as a fault.