X-Git-Url: http://git.ipfire.org/?a=blobdiff_plain;f=md.4;h=60fdd274cc50f17727f992e3422244e1c66f6cd1;hb=4ae96c802203ec3c;hp=aecff38a1d0251a73fa463c36659e5d0973f581a;hpb=5e592e1ed809b94670872b7a4629317fc1c8a5c1;p=thirdparty%2Fmdadm.git

diff --git a/md.4 b/md.4
index aecff38a..60fdd274 100644
--- a/md.4
+++ b/md.4
@@ -215,6 +215,19 @@ option or the
 .B "--update=layout-alternate"
 option.
 
+Once you have updated the layout you will not be able to mount the array
+on an older kernel.  If you need to revert to an older kernel, the
+layout information can be erased with the
+.B "--update=layout-unspecificed"
+option.  If you use this option to 
+.B --assemble
+while running a newer kernel, the array will NOT assemble, but the
+metadata will be update so that it can be assembled on an older kernel.
+
+No that setting the layout to "unspecified" removes protections against
+this bug, and you must be sure that the kernel you use matches the
+layout of the array.
+
 .SS RAID1
 
 A RAID1 array is also known as a mirrored set (though mirrors tend to