PRIMECLUSTER Global File Services Configuration and Administration Guide 4.2 (Solaris(TM) Operating Environment)

2.5 Improvement of File System Performance by Allocation of Continuous Blocks

The performance of the GFS Local File System can be improved by allocating continuous blocks for file data and thereby increasing the possibility for I/O batch operations. GFS Local File System performs extent-based area management to support this kind of allocation. For blocks that can be allocated continuously, area allocation is managed by using a combination of start offset, start block number, and the number of used blocks.

Even for file extension after allocation, GFS Local File System arranges blocks as continuously as possible.

GFS Local File System also performs an extent-based management of free data areas. This makes it possible to create an optimum allocation of free areas at high speed.