Before the original snapmirror relationship been re-established, we need to write back the updates in the node2:vol2 to node1:vol2
node1> snapmirror status
node1> snapmirror on
node2> snapmirror status
node2> snapmirror on
node1> snapmirror resync -S node2:vol2 node1:vol2
node1> snapmirror status
# There might be a problem by the same volume name, use vol rename vol2 to another volume and resync the snapmirror relation.
node1> snapmirror update -S node2:vol2 node1:vol2
# If there are some changes after resync, then update the snapmirror relation.
node1> snapmirror break node1:vol2
node2> snapmirror resync -S node1:vol2 node2:vol2
node2> snapmirror status