Hello John The situation we have here for logging is as follows: a) All logging goes via a Logger singleton. b) The output destination of the Logger is configurable at runtime. We currently have LogOutputters for file, console, and network. These LogOutputters are roughly equivalent to your appenders. c) All log messages belong to a particular topic. Topics are arranged hierarchically, which is important when considering log levels. d) All log messages also have a particular log level. These range from 'CRITICAL' all the way down to 'DEBUG4' (yes, we have four different levels of debug messages). Log levels and log topics are orthogonal to each other. e) A particular log topic can have a minimum log level specified, and any messages on that topic with levels below that level will not be logged. If a log topic does not have a level explicitly set, it inherits its level from its parent in the hierarchy, working its way up the tree until it finds a topic that has a level set. Hence, topic '/sm/message/builder' will inherit from '/sm/message', and if that has no level set then they both inherit from '/sm'. The root topic always has a level specified, even if it is the default of 'INFO'. Note that in our scheme it is impossible to turn off CRITICAL messages. f) We have a defined 'syslog' log level. All messages of that level and above are sent to the syslog, even if they are turned off for their topic. g) Log messages are sent to the LogOutputters in a structured format, with date/time, pid/tid, topic, level, and message all seperate. The LogOutputters determine how these values are formatted. h) We have the ability to adjust log levels by topic while a program is running. i) As a corollary to (h), and in contrast to what a lot of people have said, we do *not* turn off logging in our production code. However, note that all our programs are strictly 'in-house' so this is probably an unusual requirement. j) We do not do any kind of log rotation within the logging system itself. However, we do have external programs that rotate logs for us on a daily basis, and our file LogOutputter has the ability to insert a timestamp into a logfile name or append rather than overwrite on startup. Spencer ------------------------------------------------------------------------ For more information about Barclays Capital, please visit our web site at http://www.barcap.com. Internet communications are not secure and therefore the Barclays Group does not accept legal responsibility for the contents of this message. Although the Barclays Group operates anti-virus programmes, it does not accept responsibility for any damage whatsoever that is caused by viruses being passed. Any views or opinions presented are solely those of the author and do not necessarily represent those of the Barclays Group. Replies to this email may be monitored by the Barclays Group for operational or business reasons. ------------------------------------------------------------------------