If you are using the ext3 journaled file system (or potentially any
other file system/device using JBD), this option allows you to
enable debugging output while the system is running, in order to
help track down any problems you are having. By default the
debugging output will be turned off.
If you select Y here, then you will be able to turn on debugging
with "echo N > /sys/kernel/debug/jbd/jbd-debug", where N is a
number between 1 and 5, the higher the number, the more debugging
output is generated. To turn debugging off again, do
"echo 0 > /sys/kernel/debug/jbd/jbd-debug".