I have an appender configured like... <appender name="DAILY_ROLLING" class="ch.qos.logback.core.rolling.RollingFileAppender"> <File>logs/dm.log</File> <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy"> <FileNamePattern>logs/dm.%d{yyyyMMdd}.log</FileNamePattern> </rollingPolicy> <encoder> <pattern>%m%n</pattern> </encoder> </appender> ... <root level="info"> <appender-ref ref="DAILY_ROLLING" /> <appender-ref ref="SYSLOG" /> </root> ...which typically has the effect of logging current data to the dm.log file and everyday at midnight rolling over the dm.log into a file named for the date, dm.20130205.log. Yesterday, however, for the first time ever, this rollover did not occur on any of my production servers. My dm.log file now has 2 days worth of data and I am wondering what went wrong? I expected to find a RolloverFailure or some indication of what went wrong to be laying in the dm.log file but there is nothing there. I have never seen this mechanism fail in either logback or log4j and am at a loss as to where to start troubleshooting. Where do I look to figure out what went wrong in logback? Am I correct in expecting some ch.qos.logback.core.rolling.RolloverFailure stacktrace to be appearing in my dm.log file or does it only go there if my app is correctly catching and logging all throwables?