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

23.3.1 Setting the Extent Attribute Information

The GFS Shared File System has functions that allocate a data area beforehand to a file, extend a data area in a certain proportion, and guarantee data area continuity. The information that enables these functions is called extent attribute information. These functions increase performance, by ensuring data area allocation and data area continuity.

Use sfcsetext(1) to set the extent attribute information. However, you cannot use it to set this information for an existing file. To set the extent attribute information in an existing file, execute sfcsetext(1) with an alias, copy the data with sfccp(1) and change the name of alias to the original with sfcmv(1).

When an extent attribute information is set for a directory, it is automatically reflected in the files and directories created under the directory.

An example for using sfcsetext(1) is given below:

% sfcsetext -a 100,25 -f contig /mnt/file

The extent attribute information and the file allocation property cannot be set in a single file at the same time.

For details on the sfcsetext(1) options, see Appendix F.3.6, "sfcsetext(1)."