Clarify when update=super-minor happens automatcially

[thirdparty/mdadm.git] / md.4

diff --git a/md.4 b/md.4
index d22ded4231ec017e4d16454b997062dd2e5e8096..84159d91db68599486786cd4f52e2044e4f4e350 100644 (file)
--- a/md.4
+++ b/md.4
@@ -1,3 +1,9 @@
+''' Copyright Neil Brown and others.
+'''   This program is free software; you can redistribute it and/or modify
+'''   it under the terms of the GNU General Public License as published by
+'''   the Free Software Foundation; either version 2 of the License, or
+'''   (at your option) any later version.
+''' See file COPYING in distribution for details.
 .TH MD 4
 .SH NAME
 md \- Multiple Device driver aka Linux Software Raid
@@ -74,6 +80,14 @@ UUID
 a 128 bit Universally Unique Identifier that identifies the array that
 this device is part of.
 
+When a version 0.90 array is being reshaped (e.g. adding extra devices
+to a RAID5), the version number is temporarily set to 0.91.  This
+ensures that if the reshape process is stopped in the middle (e.g. by
+a system crash) and the machine boots into an older kernel that does
+not support reshaping, then the array will not be assembled (which
+would cause data corruption) but will be left untouched until a kernel
+that can complete the reshape processes is used.
+
 .SS ARRAYS WITHOUT SUPERBLOCKS
 While it is usually best to create arrays with superblocks so that
 they can be assembled reliably, there are some circumstances where an
@@ -393,7 +407,7 @@ will not wait for writes to those requests to complete before
 reporting the write as complete to the filesystem.
 
 This allows for a RAID1 with WRITE-BEHIND to be used to mirror data
-over a slow link to a remove computer (providing the link isn't too
+over a slow link to a remote computer (providing the link isn't too
 slow).  The extra latency of the remote link will not slow down normal
 operations, but the remote system will still have a reasonably
 up-to-date copy of all data.