automounted

Automounted refers to a filesystem that is mounted automatically by an automounter when its mount point is accessed. In Unix-like systems, an automounter runs as a daemon and monitors the file system namespace for requests to access certain paths. When a process touches an automount point, the kernel triggers the automounter to mount the target filesystem, such as an NFS share or a local resource, on demand. After the file system is mounted, access proceeds as normal, and the automounter may unmount it after a period of inactivity to reclaim resources.

Common implementations include the Linux autofs daemon, FreeBSD's amd, and macOS's automountd. Configuration uses map files that describe how to translate a mount point into a real source. Maps may be master maps pointing to indirect maps, which in turn specify the actual back-end resources. This on-demand approach reduces the number of permanently mounted file systems, speeds boot processes, and simplifies management of network shares and removable media.

Advantages include reduced manual mounting, automatic cleanup, resilience to unavailable targets, and smoother access to remote resources. Limitations include possible latency on first access, complexity of map configurations, and the risk of stale mounts if a server becomes unreachable. Robust automount setups depend on reliable daemon operation and correct timeout settings.

In practice, automounted file systems are common for network shares (such as NFS) and for certain desktop environments that automatically mount removable media or shared resources when accessed. The term describes any filesystem that is not mounted until needed and is managed by an automounter.