nicko 2005/05/02 14:30:22
Modified: xdocs/src/release faq.xml
Log:
Updated FAQ to include information on FileAppender MinimalLock model
Revision Changes Path
1.5 +20 -12 logging-log4net/xdocs/src/release/faq.xml
Index: faq.xml
===================================================================
RCS file: /home/cvs/logging-log4net/xdocs/src/release/faq.xml,v
retrieving revision 1.4
retrieving revision 1.5
diff -u -r1.4 -r1.5
--- faq.xml 2 May 2005 21:12:42 -0000 1.4
+++ faq.xml 2 May 2005 21:30:22 -0000 1.5
@@ -620,29 +620,37 @@
<section id="single-file" name="How do I get
multiple process to log to the same file?">
<p>
- The <span
class="code">FileAppender</span> holds a write lock on the log
- file while it is logging. This
prevents other processes from writing to the
- file, therefore it is not
possible to have multiple processes log directly
- to the same log file, even if
they are on the same machine.
- </p>
- <p>
- You may have each process log
to a <span class="code">RemotingAppender</span>.
- The receiving <span
class="code">RemoteLoggingServerPlugin</span> (or
- <span
class="code">IRemoteLoggingSink</span>) can receive all the events and
- send them to a single log file.
+ By default the <span
class="code">FileAppender</span> holds an exclusive write
+ lock on the log file while it
is logging. This prevents other processes from
+ writing to the file. The <span
class="code">FileAppender</span> can be configured
+ to use a different locking
model, <span class="code">MinimalLock</span>, that
+ only acquires the write lock
while a log is being written. This allows multiple
+ processes to interleave writes
to the same file, albeit with a loss in performance.
+ See the <a
href="config-examples.html#fileappender">FileAppender config examples</a>
+ for an example <span
class="code">MinimalLock</span> configuration.
+ </p>
+ <p>
+ While the <span
class="code">MinimalLock</span> model may be used to interleave
+ writes to a single file it may
not be the optimal solution, especially when
+ logging from multiple machines.
Alternatively you may have one or more processes
+ log to <span
class="code">RemotingAppenders</span>.
+ Using the <span
class="code">RemoteLoggingServerPlugin</span> (or
+ <span
class="code">IRemoteLoggingSink</span>) a process can receive all the events
and
+ log them to a single log file.
</p>
</section>
<p><a href="#top">Back to Top</a></p>
- <section id="distributed" name="If I have many
processes across multiple hosts (possibly across multiple time zones) logging
to the same file using the method above, what happens to timestamps?">
+ <section id="distributed" name="If I have many
processes across multiple hosts (possibly across multiple time zones) logging
to the same file using the RemotingAppender, what happens to timestamps?">
<p>
The timestamp is created when
the logging event is created. That is so say,
when the <span
class="code">Debug</span>, <span class="code">Info</span>,
<span class="code">Warn</span>,
<span class="code">Error</span>
or <span
class="code">Fatal</span> method is invoked. This is unaffected by the time at
which they may arrive at a
remote server. Since the timestamps are
- stored in UTC format inside the
event, they all appear in the same time zone as
+ transmitted in UTC format by
the <span class="code">RemotingAppender</span>,
+ they all appear in the same
time zone as
the host creating the logfile.
Since the clocks of various machines may not be
synchronized, this may account
for time interval inconsistencies between events
generated on different hosts.
