Google Search Appliance Connectors Administration Guide - Manual (Page 27)

To change the size of log files, edit the java.util.logging.FileHandler.limit value
in the logging.properties file:
java.util.logging.FileHandler.limit=10485760
Change the number of log files
The connector writes to a log file until the size limit is reached, then starts writing to a new
log file. By default, the connector writes to 20 log files, but you can change the number to
suit your needs. There is no upper limit to the number of log files. After it finishes writing to
the last log file, it starts writing over the first file.
To change the number of log files, edit the java.util.logging.FileHandler.count
value in the logging.properties file:
java.util.logging.FileHandler.count=20