add faq item re unbootable system, rootdelay

Signed-off-by: martin f. krafft <madduck@debian.org>

1 files changed, 27 insertions, 1 deletions

diff --git a/debian/FAQ b/debian/FAQ
index c7fe3b11..c7cdd8df 100644
--- a/debian/FAQ
+++ b/debian/FAQ
@@ -555,4 +555,30 @@ The latest version of this FAQ is available here:
   skip lengthy resynchronisation for arrays that have not been properly shut
   down, but which also not have changed.
 
- -- martin f. krafft <madduck@debian.org>  Wed, 02 Jul 2008 11:32:51 +0200
+26. Why doesn't mdadm find arrays specified in the config file and causes the
+    boot to fail?
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  My boot process dies at an early stage and drops me into the busybox shell.
+  The last relevant output seems to be from mdadm and is something like
+
+    "/dev/md2 does not exist"
+
+  or
+
+    "No devices listed in conf file found"
+
+  Why does mdadm break my system?
+
+  Short answer: It doesn't, the underlying devices aren't yet available yet
+  when mdadm runs during the early boot process.
+
+  Long answer: It doesn't. but the drivers of those devices incorrectly
+  communicate to the kernel that the devices are ready, when in fact they are
+  not. I consider this a bug in those drivers. Please consider reporting it.
+
+  Workaround: there is nothing mdadm can or will do against this. Fortunately
+  though, initramfs provides a method, documented at
+  http://wiki.debian.org/InitramfsDebug. Please append rootdelay=10 to the
+  kernel command line and try if the boot now works.
+
+ -- martin f. krafft <madduck@debian.org>  Wed, 13 May 2009 09:59:53 +0200