gistfile1.txt

diff --git a/swift/common/ring/builder.py b/swift/common/ring/builder.py
index b5dfcef..14e1346 100644
--- a/swift/common/ring/builder.py
+++ b/swift/common/ring/builder.py
@@ -1352,9 +1352,15 @@ class RingBuilder(object):
                 continue
             assigned_replicanths = weighted_replicas_for_dev[dev['id']]
             dev_tier = (dev['region'], dev['zone'], dev['ip'], dev['id'])
-            for i in range(len(dev_tier) + 1):
-                tier = dev_tier[:i]
-                weighted_replicas_by_tier[tier] += assigned_replicanths
+            weighted_replicas_by_tier[dev_tier] = assigned_replicanths
+
+        for tier_len in (4, 3, 2, 1):
+            tiers = set(t[:-1] for t in weighted_replicas_by_tier
+                        if len(t) == tier_len)
+            for tier in tiers:
+                weighted_replicas_by_tier[tier] = sum(
+                    r for t, r in weighted_replicas_by_tier.items()
+                    if t[:-1] == tier)
 
         # belts & suspenders/paranoia -  at every level, the sum of
         # wanted_replicas should be very close to the total number of