So far, we've seen how to mount filesystems manually. In general, if you have a filesystem that you need to mount on a regular basis, manual mounting tends to be a bit cumbersome. And for essential filesystems, such as a separate /var filesystem, manual mounting is not possible. These filesystems need to be mounted automatically at boot time, and we can tell the system to do just that by adding the appropriate entries to the /etc/fstab file. Even if you don't want the filesystem to be mounted automatically at boot, an /etc/fstab entry can make mounting easier, as we'll see in a bit.