diff --git a/doc/source/io.rst b/doc/source/io.rst
index 36d4bd89261c4..415e1a7ddaf07 100644
--- a/doc/source/io.rst
+++ b/doc/source/io.rst
@@ -2808,8 +2808,8 @@ Storing Mixed Types in a Table
 ++++++++++++++++++++++++++++++
 
 Storing mixed-dtype data is supported. Strings are stored as a
-fixed-width using the maximum size of the appended column. Subsequent
-appends will truncate strings at this length.
+fixed-width using the maximum size of the appended column. Subsequent attempts
+at appending longer strings will raise a ``ValueError``.
 
 Passing ``min_itemsize={`values`: size}`` as a parameter to append
 will set a larger minimum for the string columns. Storing ``floats,
diff --git a/pandas/io/pytables.py b/pandas/io/pytables.py
index cd8f7699a85d1..ffe4f4d4cae89 100644
--- a/pandas/io/pytables.py
+++ b/pandas/io/pytables.py
@@ -488,6 +488,9 @@ def keys(self):
         """
         return [n._v_pathname for n in self.groups()]
 
+    def __iter__(self):
+        return iter(self.keys())
+
     def items(self):
         """
         iterate on key->group
@@ -3247,7 +3250,7 @@ def validate_data_columns(self, data_columns, min_itemsize):
         # evaluate the passed data_columns, True == use all columns
         # take only valide axis labels
         if data_columns is True:
-            data_columns = axis_labels
+            data_columns = list(axis_labels)
         elif data_columns is None:
             data_columns = []
 
@@ -4084,7 +4087,7 @@ def write(self, obj, data_columns=None, **kwargs):
             obj = DataFrame({name: obj}, index=obj.index)
             obj.columns = [name]
         return super(AppendableSeriesTable, self).write(
-            obj=obj, data_columns=obj.columns, **kwargs)
+            obj=obj, data_columns=list(obj.columns), **kwargs)
 
     def read(self, columns=None, **kwargs):
 
@@ -4185,7 +4188,7 @@ def write(self, obj, data_columns=None, **kwargs):
         if data_columns is None:
             data_columns = []
         elif data_columns is True:
-            data_columns = obj.columns[:]
+            data_columns = list(obj.columns[:])
         obj, self.levels = self.validate_multiindex(obj)
         for n in self.levels:
             if n not in data_columns:
diff --git a/pandas/io/tests/test_pytables.py b/pandas/io/tests/test_pytables.py
index b08d24747bcd3..77ac1f90472fc 100644
--- a/pandas/io/tests/test_pytables.py
+++ b/pandas/io/tests/test_pytables.py
@@ -389,8 +389,9 @@ def test_keys(self):
             store['d'] = tm.makePanel()
             store['foo/bar'] = tm.makePanel()
             self.assertEqual(len(store), 5)
-            self.assertTrue(set(
-                store.keys()) == set(['/a', '/b', '/c', '/d', '/foo/bar']))
+            expected = set(['/a', '/b', '/c', '/d', '/foo/bar'])
+            self.assertTrue(set(store.keys()) == expected)
+            self.assertTrue(set(store) == expected)
 
     def test_repr(self):
 
@@ -1338,6 +1339,16 @@ def check_col(key, name, size):
                 [[124, 'abcdefqhij'], [346, 'abcdefghijklmnopqrtsuvwxyz']])
             self.assertRaises(ValueError, store.append, 'df_new', df_new)
 
+            # min_itemsize on Series with Multiindex (GH 10381)
+            df = tm.makeMixedDataFrame().set_index(['A', 'C'])
+            store.append('ss', df['B'], min_itemsize={'index': 4})
+            tm.assert_series_equal(store.select('ss'), df['B'])
+
+            # min_itemsize with MultiIndex and data_columns=True
+            store.append('midf', df, data_columns=True,
+                         min_itemsize={'index': 4})
+            tm.assert_frame_equal(store.select('midf'), df)
+
             # with nans
             _maybe_remove(store, 'df')
             df = tm.makeTimeDataFrame()