Data Sets Replicas Placements Strategy from Cost-Effective View in the Cloud

Algorithm 2

Select replica’s economic stored placements.

Input: data set , data centers set ,   stores the

   primitive data set , testing time ; pre-set average response time ;

Output: data center with lowest cost;

(01) set cc = ; //Assuming the cost is largest

(02) set ; //Initialize return data center index

(03) for each data center (except data center )

(04)  begin

(05)   //Assuming the replica stores on ;

(06)   set ; //record total response time

(07)   set ; //record access times;

(08)   for data center (except and )

(09)    begin

(10)     set ;

(11)     set ;

(12)    end

(13)   set ;

(14) if ()

(15)  continue;

(16) else

(17)  begin

(18)   calculate the storage cost using Definition 4;

(19)   set ; //transfer cost is initialized to zero

(20)   set ;

(21)   for data center (except and )

(22)    begin

(23)     calculate transfer cost using Definition 5;

(24)     calculate transfer cost using Definition 5;

(25)     set ;

(26)     set ;

(27)    end

(28)    if

(29)    ;

(30)  end

(31) end

(32) return .