mdadm.man: added encouragement to shrink filesystem before array.

[thirdparty/mdadm.git] / mdadm.8.in

diff --git a/mdadm.8.in b/mdadm.8.in
index a5d37b7e2d0420d9df332d932c3d1fef68afa2c2..05ae34f66177010707a6ea98e8f0f76c0b311d8a 100644 (file)
--- a/mdadm.8.in
+++ b/mdadm.8.in
@@ -921,6 +921,7 @@ argument given to this flag can be one of
 .BR resync ,
 .BR byteorder ,
 .BR devicesize ,
+.BR no\-bitmap ,
 or
 .BR super\-minor .
 
@@ -1003,7 +1004,7 @@ counts of total, working, active, failed, and spare devices.
 
 The
 .B devicesize
-will rarely be of use.  It applies to version 1.1 and 1.2 metadata
+option will rarely be of use.  It applies to version 1.1 and 1.2 metadata
 only (where the metadata is at the start of the device) and is only
 useful when the component device has changed size (typically become
 larger).  The version 1 metadata records the amount of the device that
@@ -1017,6 +1018,12 @@ This will cause
 to determine the maximum usable amount of space on each device and
 update the relevant field in the metadata.
 
+The
+.B no\-bitmap
+option can be used when an array has an internal bitmap which is
+corrupt in some way so that assembling the array normally fails.  It
+will cause any internal bitmap to be ignored.
+
 .ig
 .TP
 .B \-\-auto\-update\-homehost
@@ -2151,8 +2158,12 @@ space to start being used.  If the size is increased in this way, a
 are synchronised.
 
 Note that when an array changes size, any filesystem that may be
-stored in the array will not automatically grow to use the space.  The
-filesystem will need to be explicitly told to use the extra space.
+stored in the array will not automatically grow for shrink to use or
+vacate the space.  The 
+filesystem will need to be explicitly told to use the extra space
+after growing, or to reduce its size
+.B prior
+to shrinking the array.
 
 Also the size of an array cannot be changed while it has an active
 bitmap.  If an array has a bitmap, it must be removed before the size
@@ -2182,7 +2193,8 @@ increase or decrease the number of devices in a RAID5 or RAID6.
 
 When decreasing the number of devices, the size of the array will also
 decrease.  If there was data in the array, it could get destroyed and
-this is not reversible.  To help prevent accidents,
+this is not reversible, so you should firstly shrink the filesystem on
+the array to fit within the new size.  To help prevent accidents,
 .I mdadm
 requires that the size of the array be decreased first with
 .BR "mdadm --grow --array-size" .