Allocating files in a file system integrated with a RAID disk sub-system

摘要

Integrating a file system with a RAID array that exports precise information about the arrangement of data blocks in the RAID subsystem. The present invention uses separate current-write location (CWL) pointers for each disk in the disk array where the pointers simply advance through the disks as writes occur. The present invention writes on the disk with the lowest CWL pointer. A new disk is chosen only when the algorithm starts allocating space for a new file, or when it has allocated N blocks on the same disk for a single file. A sufficient number of blocks are defined as all the buffers in a chunk of N sequential buffers in a file. The result is that CWL pointers are never more than N blocks apart on different disks, and large files have N consecutive blocks on the same disk.