The log files are saved on a different volume than the data and journals.

In 2.6, when the log volume is full, it stop writing to the log file. However, when we free the disk space, it does not write to the log file any more. We have to run logrotate command will trigger it to continue writing to the log file. This is different than 2.2/2.4.

In 2.2 and 2.4, when the log volume is full, it also stops writing to the log file. When we free the disk space, it would continue writing to the log file like this:

Tue Jul 29 20:34:57.822 [conn1] insert test.docs ninserted:1 keyUpdates:0 locks(micrTue Jul 29 20:35:26.093 [journal] _groupCommit 
Tue Jul 29 20:35:26.093 [journal] _groupCommit upgrade