Update howto with notes on dracut and kernel watchdog module handling.
Signed-off-by: Pratyush Anand <panand(a)redhat.com>
---
kexec-kdump-howto.txt | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/kexec-kdump-howto.txt b/kexec-kdump-howto.txt
index b4cdc2227f1d..1cf726670981 100644
--- a/kexec-kdump-howto.txt
+++ b/kexec-kdump-howto.txt
@@ -616,6 +616,22 @@ options are copied from /proc/cmdline. In general it is best to
append
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 was being saved. When dracut watchdog module is enabled, it
+installs kernel watchdog module of active watchdog device in initrd. Thus,
+an user can control addition or omission of active watchdog module in crash
+kernel by adding "-a watchdog" or "-o watchdog" in dracut_args of
+kdump.conf respectively. When none of these options is passed in
+dracut_args then addition is taken as default by kexec-tools. If a
+watchdog module (such as hp_wdt) has not been written using 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
--
2.5.5