Which directories must remain on the same partition?

Partition Considerations

/bin: The /bin directory contains essential executable binaries that the system uses during the boot process. Placing /bin on a separate partition ensures that crucial commands are always accessible, even if other partitions are not mounted.

/lib: The /lib directory houses essential library files required by programs and the operating system. Keeping /lib on the same partition as /bin ensures that the necessary libraries are always available.

/etc: The /etc directory contains configuration files for system utilities, services, and applications. Keeping /etc on the same partition is crucial for proper system functioning, as many processes rely on the configurations stored in this directory.

Benefits of Separating File Systems

Separating directories like /home, /usr, /var, /tmp, and /opt into distinct file systems offers several advantages:

Isolation of Temporary and Logging Space: By separating directories like /var and /tmp, you prevent them from consuming the entire root disk with temporary or log files. This isolation ensures that system-critical files have enough space to operate smoothly.

Optimal Mount Parameters: Each file system can have unique mount parameters tailored to its specific use case. This flexibility allows for better control and optimization of disk space usage and performance.

Enhanced Security: Unprivileged users can access many files in the system, especially those in the /etc directory. However, by separating sensitive files and removing world-readable or group-readable permissions, you can enhance security and protect critical configurations from unauthorized access.

Overall, a well-thought-out partition strategy that balances the need for essential directories to remain on the same partition with the benefits of separating file systems can optimize system performance, security, and reliability.