1. An apparatus for use in a distributed, segmented single file system implemented by file servers that control metadata of separate segments of the single file system, the single file system including file system entities residing in the segments and comprising at least portions of at least one of files and directories, the apparatus comprising: memory communication means fix communicating with a memory that is configured to store a shadow structure, wherein the shadow structure resides on one segment and defines at least one relationship between a system entity residing on the one segment and a system entity residing on another segment, wherein one server is to control the system entity residing on the one segment and another server is to control the system entity residing on the another segment; and crawler means, coupled to the memory communication means, for analyzing shadow structure entries in the shadow structure stored in the memory and verifying whether the shadow structure entries represent valid links to at least one of other shadow entries and file system entities of the distributed file system; wherein the crawler means is configured to analyze shadow structure entities comprising: an inbound entry stored on a first segment and indicating that a second directory residing on a second segment points to a first file system entity stored on the first segment; and an outbound entry stored on the first segment and indicating that a first directory, residing on the first segment points to a second file system entity stored on the second segment.