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

8.2 Defragmentation Policies

Defragmentation has the following policies based on usage:

• simple policy

  The number of extents is reduced and file access performance improved by making contiguous the extents allocated to files.

  If an entire file or part of a file area is allocated again, the area is allocated from large free extents.

  If free extents are sufficiently large, defragmentation can be performed faster compared with that done using other policies (adjacent and evacuate).

• adjacent policy

  The number of extents is reduced and file access performance improved by making contiguous the extents allocated to files.

  If free extents exist after the extents to be defragmented, the free extents are allocated contiguously.

• evacuate policy

  The number of extents is reduced and file access performance improved by making contiguous the extents allocated to files.

  If the extents after the extents to be defragmented are used by other files, they are allocated forcibly moved and allocated contiguously.

  Although time is required to forcibly move the extents used by other files, this policy provides ideal defragmentation.

• free policy

  Large free extents are created by making the fragmented free extents contiguous in the file system.

• dircomp policy

  Unnecessary entries in the directory are deleted and the directory compressed.