diff -ruN anaconda-13.21.215/storage/devices.py.orig anaconda-13.21.215/storage/devices.py
--- anaconda-13.21.215/storage/devices.py.orig	2014-01-02 09:58:16.798914618 -0500
+++ anaconda-13.21.215/storage/devices.py	2014-01-02 09:58:16.818914522 -0500
@@ -1880,7 +1880,7 @@
 
         # TODO: validate peSize if given
         if not self.peSize:
-            self.peSize = 4.0   # MB
+            self.peSize = 32.0   # MB
 
         if not self.exists:
             self.pvCount = len(self.parents)
@@ -2250,6 +2250,11 @@
         used = sum(lv.vgSpaceUsed for lv in self.lvs) + self.snapshotSpace
         used += self.reservedSpace
         free = self.size - used
+
+        pad = self.peSize * 2 * len(self.pvs)
+        if free >= pad:
+            free -= pad
+
         log.debug("vg %s has %dMB free" % (self.name, free))
         return free