I am using logback within tomcat using the sifting appender. Occasionally I see &quot;IO failure in appender java.nio.channels.ClosedChannelException&quot; exception in catalina.out. I have prudent mode set to true, and although I have multiple webapps deployed, only one is actually logging messages, though it is doing so from shared libraries as well as app code and multi-threaded. I am using slf4j 1.6.1 and logback 1.0.3. How can I debug this issue? Configuration and full stack below:<div>
<br></div><div><div>&lt;configuration&gt;</div><div><br></div><div>  &lt;statusListener class=&quot;ch.qos.logback.core.status.OnConsoleStatusListener&quot; /&gt;</div><div><br></div><div>  &lt;appender name=&quot;SIFT&quot; class=&quot;ch.qos.logback.classic.sift.SiftingAppender&quot;&gt;</div>
<div>    &lt;discriminator class=&quot;ch.qos.logback.classic.sift.JNDIBasedContextDiscriminator&quot;&gt;</div><div>      &lt;defaultValue&gt;unknown&lt;/defaultValue&gt;</div><div>    &lt;/discriminator&gt;</div><div>    &lt;sift&gt;</div>
<div>      &lt;appender name=&quot;FILE-${contextName}&quot; class=&quot;ch.qos.logback.core.rolling.RollingFileAppender&quot;&gt;</div><div>        &lt;prudent&gt;true&lt;/prudent&gt;</div><div>        &lt;rollingPolicy class=&quot;ch.qos.logback.core.rolling.TimeBasedRollingPolicy&quot;&gt;</div>
<div>          &lt;!-- daily rollover --&gt;</div><div>          &lt;fileNamePattern&gt;${catalina.home}/logs/${contextName}.%d{yyyy-MM-dd}.log&lt;/fileNamePattern&gt;</div><div><br></div><div>          &lt;!-- keep 90 days&#39; worth of history --&gt;</div>
<div>          &lt;maxHistory&gt;90&lt;/maxHistory&gt;</div><div>        &lt;/rollingPolicy&gt;</div><div>        &lt;encoder&gt;</div><div>          &lt;pattern&gt;%logger{35}[%level|%thread|%d{HH:mm:ss}]: %msg%n&lt;/pattern&gt;</div>
<div>        &lt;/encoder&gt;</div><div>      &lt;/appender&gt;</div><div>    &lt;/sift&gt;</div><div>  &lt;/appender&gt;</div><div><br></div><div>  &lt;root level=&quot;INFO&quot;&gt;</div><div>    &lt;appender-ref ref=&quot;SIFT&quot; /&gt;</div>
<div>  &lt;/root&gt;</div><div>&lt;/configuration&gt;</div><div><br></div><div><br></div><div>10:20:05,777 |-ERROR in ch.qos.logback.core.rolling.RollingFileAppender[FILE-jobs.v1] - IO failure in appender java.nio.channels.ClosedChannelException</div>
<div><div>        at java.nio.channels.ClosedChannelException</div><div>        at      at sun.nio.ch.FileChannelImpl.ensureOpen(FileChannelImpl.java:88)</div><div>        at      at sun.nio.ch.FileChannelImpl.position(FileChannelImpl.java:243)</div>
<div>        at      at ch.qos.logback.core.FileAppender.safeWrite(FileAppender.java:188)</div><div>        at      at ch.qos.logback.core.FileAppender.writeOut(FileAppender.java:204)</div><div>        at      at ch.qos.logback.core.OutputStreamAppender.subAppend(OutputStreamAppender.java:211)</div>
<div>        at      at ch.qos.logback.core.rolling.RollingFileAppender.subAppend(RollingFileAppender.java:148)</div><div>        at      at ch.qos.logback.core.OutputStreamAppender.append(OutputStreamAppender.java:102)</div>
<div>        at      at ch.qos.logback.core.UnsynchronizedAppenderBase.doAppend(UnsynchronizedAppenderBase.java:88)</div><div>        at      at ch.qos.logback.core.sift.SiftingAppenderBase.append(SiftingAppenderBase.java:94)</div>
<div>        at      at ch.qos.logback.core.AppenderBase.doAppend(AppenderBase.java:85)</div><div>        at      at ch.qos.logback.core.spi.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:53)</div>
<div>        at      at ch.qos.logback.classic.Logger.appendLoopOnAppenders(Logger.java:282)</div><div>        at      at ch.qos.logback.classic.Logger.callAppenders(Logger.java:269)</div><div>        at      at ch.qos.logback.classic.Logger.buildLoggingEventAndAppend(Logger.java:470)</div>
<div>        at      at ch.qos.logback.classic.Logger.filterAndLog_0_Or3Plus(Logger.java:424)</div><div>        at      at ch.qos.logback.classic.Logger.error(Logger.java:583)</div></div><div><br></div></div><div>After failure, the appender seems to recover, but I assume I am losing log messages:</div>
<div><br></div><div><div>10:25:56,689 |-WARN in ch.qos.logback.core.rolling.RollingFileAppender[FILE-jobs.v1] - Attempted to append to non started appender [FILE-jobs.v1].</div><div>10:25:56,724 |-WARN in ch.qos.logback.core.rolling.RollingFileAppender[FILE-jobs.v1] - Attempted to append to non started appender [FILE-jobs.v1].</div>
<div>10:25:56,738 |-WARN in ch.qos.logback.core.rolling.RollingFileAppender[FILE-jobs.v1] - Attempted to append to non started appender [FILE-jobs.v1].</div><div>10:25:57,449 |-INFO in ch.qos.logback.core.joran.action.AppenderAction - About to instantiate appender of type [ch.qos.logback.core.rolling.RollingFileAppender]</div>
<div>10:25:57,449 |-INFO in ch.qos.logback.core.joran.action.AppenderAction - Naming appender as [FILE-jobs.v1]</div><div>10:25:57,450 |-INFO in c.q.l.core.rolling.TimeBasedRollingPolicy - No compression will be used</div>
<div>10:25:57,450 |-INFO in c.q.l.core.rolling.TimeBasedRollingPolicy - Will use the pattern /etc/webserver/logs/jobs.v1.%d{yyyy-MM-dd}.log for the active file</div><div>10:25:57,450 |-INFO in c.q.l.core.rolling.DefaultTimeBasedFileNamingAndTriggeringPolicy - The date pattern is &#39;yyyy-MM-dd&#39; from file name pattern &#39;/etc/webserver/logs/jobs.v1.%d{yyyy-MM-dd}.log&#39;.</div>
<div>10:25:57,450 |-INFO in c.q.l.core.rolling.DefaultTimeBasedFileNamingAndTriggeringPolicy - Roll-over at midnight.</div><div>10:25:57,450 |-INFO in c.q.l.core.rolling.DefaultTimeBasedFileNamingAndTriggeringPolicy - Setting initial period to Tue Aug 28 10:25:57 PDT 2012</div>
<div>10:25:57,450 |-INFO in ch.qos.logback.core.joran.action.NestedComplexPropertyIA - Assuming default type [ch.qos.logback.classic.encoder.PatternLayoutEncoder] for [encoder] property</div><div>10:25:57,451 |-INFO in ch.qos.logback.core.rolling.RollingFileAppender[FILE-jobs.v1] - Active log file name: /etc/webserver/logs/jobs.v1.2012-08-28.log</div>
<div>10:25:57,451 |-INFO in ch.qos.logback.core.rolling.RollingFileAppender[FILE-jobs.v1] - File property is set to [null]</div></div><div><br></div>