Defragmentation utility for a shared disk parallel file system across a storage area network

A computer readable medium including programming instructions for defragmentation of a shared file system storage network associated with a plurality of processing nodes, the programming instructions for execution on a processing node comprising instructions for performing the steps of:

• (a) stepping through file metadata in a file structure in order to find a file fragment, the file fragment being a file or part of a file that occupies m sub-blocks of a disk block, where each disk block is divided into n sub-blocks that can be allocated independently, and m<n;
• and
• (b) when a file fragment is found, determining if the file fragment is located in a first list or a second list, or if the file fragment is located in a full disk block;
• (c) if the file fragment is not located in the first list or the second list, and the file fragment is not located in a full block, searching for a suitable hole in the first list;
• and
• (d) if the suitable hole is found in the first list, migrating the file fragment to the suitable hole,
• wherein a full disk block has all of its sub-blocks occupied,
• the first list contains disk blocks each having at least one hole because not all of its sub-blocks are occupied, and
• the second list contains disk blocks in which any file fragments are currently not allowed to be migrated.

A method for backing-off of a defragmentation of a shared file system storage network associated with a plurality of processing nodes, the method on a processing node comprising the steps of:

• stepping through file metadata in a file structure in order to find a file fragment, the file fragment being a file or part of a file that occupies m sub-blocks of a disk block, where each disk block is divided into n sub-blocks that can be allocated independently, and m<n;
• and
• when a file fragment is found, searching for a suitable hole in a first list;
• if the suitable hole has been found, determining if a current state of the hole is different than that recorded in the first list;
• if the current state is not different, migrating the file fragment into the suitable hole, and freeing the sub-blocks previously occupied by the file fragment;
• and
• if the current state is different, updating the current state of the hole, and checking the first list again to search for another suitable hole in the first list.

A shared file system storage network associated with a plurality of processing nodes, a processing node for defragmenting shared files comprising:

• an interface to one or more file storage systems;
• means for stepping through file metadata in a file structure on the storage network in order to find a file fragment, the file fragment being a file or part of a file that occupies m sub-blocks of a disk block, where each disk block is divided into n sub-blocks that can be allocated independently, and m<n;
• means for, when a file fragment is found, determining if the file fragment is located in a first list or a second list, or if the file fragment is located in a full disk block;
• means for, if the file fragment is not located in the first list or the second list, and the file fragment is not located in a full block, searching for a suitable hole in the first list;
• and
• means for, if the suitable hole is found in the first list, migrating the file fragment to the suitable hole,
• wherein a full disk block has all of its sub-blocks occupied, the first list contains disk blocks each having at least one hole because not all of its sub-blocks are occupied, and
• the second list contains disk blocks in which any file fragments are currently not allowed to be migrated.