SQL database log files can grow significantly, especially during an upgrade. One must be sure enough disk space exists to perform upgrades. The approximate space needed to perform the upgrade should be determined by the size of the database. It should be approximately twice the size of the database.
It is strongly recommended that the log file be shrunk after an upgrade and periodically thereafter as part of regular database maintenance. For more information about shrinking the SiteAudit database log file, refer to the Shrink Database Log File article