Add an example to generate a random XFS UUID to man page.

This alternative to the "mount -o nouuid" approach is useful for long-lived
snapshots.

diff --git a/misma.suite.m4 b/misma.suite.m4
index 46493fd727776877fc319b903fb98b1237120b04..41893f9c714b299ff9a06dcb1726ba9436e9e1b4 100644 (file)
--- a/misma.suite.m4
+++ b/misma.suite.m4
@@ -449,15 +449,12 @@
        .I activate
        the snapshot logical volume to create the corresponding device node.
 
-       Moreover, the XFS filesystem driver refuses to mount a block device
-       which contains a UUID that is identical to the UUID of an already
-       mounted filesystem. To mount a snapshot of an XFS filesystem, one
-       must therefore tell XFS to skip the UUID check.
+       Moreover, the XFS filesystem driver refuses to mount a filesystem whose
+       UUID is identical to the UUID of an already mounted filesystem. To mount a
+       snapshot of a mounted XFS filesystem, one must therefore either change the
+       UUID of the snapshot, or ask XFS to skip the UUID check.
 
-       See the examples below for suitable command line options for
-       .BR lvchange (8)
-       and
-       . BR mount (8).
+       See the examples below for suitable commands to work around these issues.
 
        Since logical volumes which contain a mounted filesystem cannot be
        removed, a thin pool which is not overbooked may still run out of
@@ -541,7 +538,16 @@
        .EE
        .RE
        .IP \(bu 2
-       Mount an active snapshot which contains an XFS filesystem:
+       Replace the UUID of the XFS filesystem stored on a snapshot with a random UUID:
+
+       .RS 6
+       .EX
+               .B xfs_admin \-U generate /dev/vg/misma-tlv.42
+       .EE
+       .RE
+       .IP \(bu 2
+       Mount an active snapshot which contains an XFS filesystem, ignoring duplicate
+       UUIDs:
 
        .RS 6
        .EX