On Tue, 1 Jul 2008 09:34:00 +1000 "Mark Harvey" <[EMAIL PROTECTED]> wrote:
> Hi Tomasz, > > I've also noticed there is only one tgtd process when running it in > the foreground. > > Running in the foreground has been the only way I've been successful > in collecting core files in the past. > > I still do not (read: never actually spent time looking) understand > the why/what differences is between foreground and why there is two > processes while in background. We have two tgtd processes to write a log file safely (to avoid blocking). Let's suppose that we have only one tgtd process. The process calls syslog to write a log file. In an out-of-memory situation, syslog() blocks. It means that the process might sleeps for long time. We can't perform any SCSI processes so that commands from initiators are likely to be aborted due to timeout. With '-f' option, tgtd works in this way. By default, we have two processes. They use shared memory. The main process performs everything except for logging. The process writes a log message to the shared memory instead of calling syslog(). Another (logging) process calls syslog to write the message in the shared memory to a log file. In an out-of-memory situation, the logging process might sleep for long time but the main process doesn't. If the shared memory is full, a log message is lost but the main process always works for initiators. _______________________________________________ Stgt-devel mailing list [email protected] https://lists.berlios.de/mailman/listinfo/stgt-devel
