Update howto with notes on dracut and kernel watchdog module handling.
Signed-off-by: Pratyush Anand <panand(a)redhat.com>
kexec-kdump-howto.txt | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/kexec-kdump-howto.txt b/kexec-kdump-howto.txt
index b4cdc2227f1d..38f831e8acfb 100644
@@ -616,6 +616,20 @@ options are copied from /proc/cmdline. In general it is best to
command line options using "KDUMP_COMMANDLINE_APPEND=" instead of replacing
the original command line completely.
+Notes on watchdog module handling:
+If a watchdog is active in first kernel then, we must have it's module
+loaded in crash kernel, so that either watchdog is deactivated or started
+being kicked in second kernel. Otherwise, we might face watchdog reboot
+when vmcore is being saved. When dracut watchdog module is enabled, it
+installs kernel watchdog module of active watchdog device in initrd.
+kexec-tools always add "-a watchdog" to the dracut_args if there exists at
+least one active watchdog and user has not added specifically "-o watchdog"
+in dracut_args of kdump.conf. If a watchdog module (such as hp_wdt) has
+not been written in watchdog-core framework then this option will not have
+any effect and module will not be added. Please note that only systemd
+watchdog daemon is supported as watchdog kick application.
Parallel Dumping Operation
Kexec allows kdump using multiple cpus. So parallel feature can accelerate