UFS logging saves time when you reboot after a failure, because it eliminates the need to run the fsck(1M) command on file systems.
What are the drawbacks to UFS logging?
If the log fills up, performance can decrease because the UFS must empty the log before writing new information into it.
What versions of Solaris work with UFS logging?
UFS logging can only be used with Solaris 2.4 or later releases.
Non-UFS file systems as well as the root (/) file system cannot be logged.