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

25.1 Update Log

For high speed file system recovery, the GFS Shared File System writes to the disk an update log, which keeps a record of changes in the file system structure. Keeping an update log may give the impression that more I/O operations occur than in conventional file systems, but this is not true. As a result of reducing file meta-data I/O operations, a file system with this log has file system performance equal to or greater than that of file systems without the log. The reduction in operations occurs because changes are written as a batch and the reflection of update data is delayed. To receive these benefits, pay attention the following regarding the characteristics of the update log and actual file system access:

• Is the size of the update log area sufficient?
• Is the size of the update log area too large?
• Should the update log area be separated and placed in another partition?

The following sections consider each of these questions.

To change the settings for the update log area, use sfcadm(1M) to resize the area.

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25.1.1 Is the size of the update log area sufficient?

25.1.2 Is the size of the update log area too large?

25.1.3 Should the update log area be separated and placed in another partition?