I have this vague recollection of there being a switch you can configure syslog with which would force it to flush logs to disk right away so when your system hung you might be able to get some useful information out of it. Right now I'm getting a block full of zeroes '\0' where the block for the file was allocated but the log data never actually made it to disk. Did I dream that or am I just having a bad google day? (ubuntu 14.04)
I'm not familiar with a syslog implementation that has a command line option to flush logs to disk. Many syslog implementations flush logs to disk by default, but do not flush if the name of the log file in the syslog configuration file (e.g.
/etc/syslog.conf) is preceded by a
- (dash). This may be what you remember.