Unfortunately there's not a uniform way to rotate log files. The server code uses Log4j for configuring, writing and rotating log files. To change the configuration for zimbrastats.csv, edit the following section in /opt/zimbra/conf/log4j.properties:
Code:
# Appender STATS writes to the file "zimbrastats.csv".
log4j.appender.STATS=org.apache.log4j.ZimbraStatsAppender
log4j.appender.STATS.File=/opt/zimbra/log/zimbrastats.csv
log4j.appender.STATS.DatePattern='.'yyyy-MM-dd
log4j.appender.STATS.Append=true
log4j.appender.STATS.layout=org.apache.log4j.PatternLayout
log4j.appender.STATS.layout.ConversionPattern=%m%n
ZimbraStatsAppender is a hack of Log4j's DailyRollingFileApender class. The Log4j Javadoc has the details about configuration options.