log4net 1.2.12, rolling file appender quits logging after some time

[Douglas Neary]

All:

First time poster, long time user.   Thanks for a great tool.

The background:
I have log4net version 1.2.12 of log4net running on Windows Server 2008 R2.  
This is an Asp.net application (.Net 3.5.1) with 3 separate web sites logging 
to 3 separate log files using the rolling file appender.    Log4net internal 
logging enabled for all 3 sites and directed to separate files.  I can post 
that output, but I did not as it is very verbose.

I was having a similar problem with log4net 1.2.10, I just updated to 1.2.12.

The good news:
Logging works fine for all 3 sites, for a while.

The problem:
2 of the 3 logs quit writing after a while (hours, maybe a day or so max).  In 
the log4net internal logs, I see the following text written over and over 
(looks to be every time logging is attempted)
log4net: Opening file for writing [c:\logs\logfile2.log] append [False] or
log4net: Opening file for writing [c:\logs\logfile3.log] append [False]
The questions:
Can I get a timestamp emitted (or any other formatting) with log4net internal 
debugging?
Any idea how to track down root cause on why these 2 loggers quit logging after 
a while?

The web.config:
Snip of log4net from web.config from 1 site below.  The other 2 sites are 
identical except for the log file name.

  <log4net>
    <appender name="ConsoleAppender" type="log4net.Appender.ConsoleAppender">
      <layout type="log4net.Layout.PatternLayout">
        <param name="ConversionPattern" value="%d [%t] %-5p %c [%x] - %m%n"/>
      </layout>
    </appender>
    <appender name="RollingLogFileAppender" 
type="log4net.Appender.RollingFileAppender">
      <param name="File" value="c:\logs\logfile1.log"/>
      <param name="AppendToFile" value="true"/>
      <param name="MaxSizeRollBackups" value="10"/>
      <param name="MaximumFileSize" value="100MB"/>
      <param name="RollingStyle" value="Size"/>
      <param name="StaticLogFileName" value="true"/>
      <layout type="log4net.Layout.PatternLayout">
        <!-- do not alter ConversionPattern, it is used for reporting.-->
        <param name="ConversionPattern" value="%date{yyyy-MM-dd HH:mm:ss.fff} 
[%t] [%x] %p %c - %m%n"/>
      </layout>
    </appender>
    <root>
      <level value="Info"/>
      <appender-ref ref="RollingLogFileAppender"/>
      <appender-ref ref="ConsoleAppender"/>
    </root>
  </log4net>

Thanks in advance for any guidance.

Doug