mdadm.man add encouragement to shrink filesystem before shrinking array.

Before resizing an array with --size or --array-size, then filesystem
should be resized.  mdadm cannot do this so the user should.

Reported-by: Gavin Flower <gavinflower@yahoo.com>
Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 23 insertions, 0 deletions

diff --git a/mdadm.8.in b/mdadm.8.in
index 8ffeb26d..a5d37b7e 100644
--- a/mdadm.8.in
+++ b/mdadm.8.in
@@ -424,6 +424,18 @@ The size can be given as
 .B max
 which means to choose the largest size that fits on all current drives.
 
+Before reducing the size of the array (with
+.BR "\-\-grow \-\-size=" )
+you should make sure that space isn't needed.  If the device holds a
+filesystem, you would need to resize the filesystem to use less space.
+
+After reducing the array size you should check that the data stored in
+the device is still available.  If the device holds a filesystem, then
+an 'fsck' of the filesystem is a minimum requirement.  If there are
+problems the array can be made bigger again with no loss with another
+.B "\-\-grow \-\-size="
+command.
+
 This value can not be used with
 .B CONTAINER
 metadata such as DDF and IMSM.
@@ -675,6 +687,17 @@ A value of
 restores the apparent size of the array to be whatever the real
 amount of available space is.
 
+Before reducing the size of the array you should make sure that space
+isn't needed.  If the device holds a filesystem, you would need to
+resize the filesystem to use less space.
+
+After reducing the array size you should check that the data stored in
+the device is still available.  If the device holds a filesystem, then
+an 'fsck' of the filesystem is a minimum requirement.  If there are
+problems the array can be made bigger again with no loss with another
+.B "\-\-grow \-\-array\-size="
+command.
+
 .TP
 .BR \-N ", " \-\-name=
 Set a