Zombie Process
An inactive server process that has completed execution but remains in the system, unnecessarily consuming minor resources until fully cleared.
A zombie process is a terminated process that has finished executing but still has an entry in the server's process table because its parent process hasn't yet read its exit status. While zombie processes don't consume CPU or memory resources, they do occupy a slot in the process table, and large numbers of them can eventually exhaust available process IDs, potentially affecting server performance. Zombies typically exist only briefly in well-designed systems, appearing momentarily between when a process completes and when its parent acknowledges the completion. However, poorly written applications or scripts that don't properly handle child processes can create persistent zombies. In hosting environments, system administrators monitor for zombie processes and address any applications creating excessive numbers of them. For most website owners, zombie processes are handled automatically by the server's operating system and hosting management tools, but understanding them helps when diagnosing unusual server behaviour or resource issues reported in hosting dashboards.
