anchor.diff:       {vb_avg_total_queue_age, AvgTotalQueueAge},
        {vb_active_resident_items_ratio, ActiveResRate},
        {vb_replica_resident_items_ratio, ReplicaResRate},
  -     {vb_pending_resident_items_ratio, PendingResRate}].
  +     {vb_pending_resident_items_ratio, PendingResRate},
  +     {avg_write_seek_distance, AverageWriteSeekDistance}].
   
   %% converts list of samples to proplist of stat values.
   %%
  
positive.code:                           {desc, <<"High water mark for auto-evictions (measured from ep_mem_high_wat)">>}]},
                  {struct, [{title, <<"low water mark">>},
                            {name, <<"ep_mem_low_wat">>},
                            {desc, <<"Low water mark for auto-evictions (measured from ep_mem_low_wat)">>}]}
               ]}]},
       {struct,[{blockName,<<"vBucket Resources">>},
                {extraCSSClasses,<<"withtotal closed">>},
  
negative.code:                         ResidenceCalculator),
      PendingResRate = Z2(vb_pending_num_non_resident, vb_pending_curr_items,
                          ResidenceCalculator),
  
      AverageWriteSeekDistance = Z2(write_seeks_distance, write_seeks_count,
                                    fun (Distance, Count) ->
                                            try Distance / Count
                                            catch error:badarith -> 0
                                            end
                                    end),
  
      [{hit_ratio, HitRatio},
       {ep_cache_miss_rate, EPCacheMissRatio},
       {ep_resident_items_rate, ResidentItemsRatio},
  