Hello everyone! I've come across an issue with RollingFileAppender, but I'm not sure if it's us or logback. <configuration> <timestamp key="currentDate" datePattern="yyyy_MM_dd" /> <appender name="dataServiceRequestLog" class="ch.qos.logback.core.rolling.RollingFileAppender"> <param name="File" value="${the.log.dir}/${currentDate}.WebService.log"/> <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy"> <FileNamePattern>${the.log.dir}/%d{yyyy_MM_dd}.WebService.log</FileNamePattern> <MaxHistory>30</MaxHistory> </rollingPolicy> <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder"> <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level - %msg%n</pattern> </encoder> </appender> The curious part is that File matches the FileNamePattern for the rolling policy ("${the.log.dir}/${currentDate}.WebService.log" and "${the.log.dir}/%d{yyyy_MM_dd}.WebService.log"). Do you guys think that's OK? The intention is that there's a separate file for every day: - 2013_01_03.WebService.log - 2013_01_04.WebService.log - 2013_01_05.WebService.log - 2013_01_06.WebService.log The issue we're experiencing is seemingly random writes to old log files (e.g., today we saw writes to 2013_01_04.WebService.log). Could this be the rename problem? Perhaps there's a better way to achieve the desired functionality. Is this worth writing a unit test for in RollingFileAppenderTest.java? Any tips are greatly appreciated, thanks!