There are two types of filesystem maintenance: partition and content maintenance. The former includes periodic checking of the filesystem's underlying structure and metadata, modifying the partition layout, and low-level backups. The latter involves monitoring and controlling the space used by files as well as file backup and recovery.
Although modern journaling filesystems are quite resilient, they will, on occasion, suffer an error in the underlying infrastructure. The reasons are many and include power fluctuations, hardware failures, and certain types of kernel failures. While the last is extremely rare in Debian stable releases, it does happen, especially if third-party kernel modules that are not ...