Free CompTIA Linux+ Questions

Which of the following directories must be mounted with read and write access if it resides on its own dedicated file system?

A. /opt
B. /lib
C. /etc
D. /var
E. /usr

Answer: D

/var contains variable data like system logging files, mail and printer spool directories, and transient and temporary files. Some portions of /var are not shareable between different systems. For instance, /var/log, /var/lock, and /var/run. Other portions may be shared, notably /var/mail, /var/cache/man, /var/cache/fonts, and /var/spool/news. Why not put it into /usr? Because there might be circumstances when you may want to mount /usr as read-only, e.g. if it is on a CD or on another computer. '/var' contains variable data, i.e. files and directories the system must be able to write to during operation, whereas /usr should only contain static data. Some directories can be put onto separate partitions or systems, e.g. for easier backups, due to network topology or security concerns. Other directories have to be on the root partition, because they are vital for the boot process. 'Mountable' directories are: '/home', '/mnt', '/tmp', '/usr' and '/var'. Essential for booting are: '/bin', '/boot', '/dev', '/etc', '/lib', '/proc' and '/sbin'.