File management system

A file management system comprising:

• a plurality of disk devices, managed in the form of a disk pool, of which at least two disk devices are dynamically selected from said disk pool, constituting a plurality of files storing in redundancy any one set of data of user data and meta data for managing how the user data are used;
• and
• a file system, constituting a part of an operating system of a host computer, managing said plurality of disk devices as said disk pool and managing en bloc the files, based on the meta data, wherein said file system, in the case of file of less than one block, selects two of said plurality of disk devices in said disk pool, and makes the user data stored in the redundancy of a RAID level 1, wherein said file system, in the case of a file of over two blocks, selects three or more of said plurality of disk devices in said disk pool, and makes the user data stored in the redundancy of a RAID level 5, wherein said file system makes the meta data stored in predetermined two of said plurality of disk devices in said disk pool in the redundancy of the RAID level 1, wherein the meta data is stored on a file-basis with an address conversion table including a disk number of said disk device stored with the user data, and disk block number corresponding to an intra-disk relative block number.

A file management system comprising:

• a plurality of disk devices, managed in the form of a disk pool, of which at least two disk devices are dynamically selected from said disk pool, constituting a plurality of files storing in redundancy any one set of data of user data and meta data for managing how the user data are used;
• and
• a file system, constituting a part of an operating system of a host computer, managing said plurality of disk devices as said disk pool and managing en bloc the files, based on the meta data, wherein said file system caches the user data when writing the data in order to restrain an occurrence of recalculation of the parity data, and delays an allocation of the disk block till the file is closed or said cache becomes full.