RER： A Replica Efficiency Based Replication Strategy.pdfVIP

ChineseJournalofElectronics V_o1．17，No．4，Oct．2008 RER：A ReplicaEfficiencyBased Replication Strategy术 FENG Guofu ，一，ZHANG Jincheng ，LU Sanglu ，CHEN Guihai。andCHEN Daoxu (1．SchoolofInformationScience，NanjingAuditUniversity，Nanjing210029，China) (2．DepartmentofComputerScienceandTechnology，NanjingUniversity，Nanjing210093,China) A bstract— Thetechnology ofreplication isoften used cessivereplicasofrthepopularobjectswilldamagetheperfor— intheunstructuredPeer．to-peerfP2P)systemstoallocate manceofthelesspopular，whereas thescarcitycannotimprove m orereplicasforthehotspotsin orderforahighersearch thesearchperformanceenough．Thenwhatisthethreshold perform ance．Butthe questionsthatwhat isthe optimal ofrthepopular，andifgiventhelimitedstoragespacewhatis num ber ofcopies of r each file and what is the practica- theappropriateallocation amongtheentirefiles? Moreover， ble approach to the optim alhaITIberare seldom answered in therelated works．In term sofSuccessrate，thisPaPer evenifgiventheoptimalallocation，how toimplementthede— firstly investigatestheoptim alallocation ofcopiesof reach ploymentinthepurelydistributedP2Pwithlittleglobalinofr— fileaccording to query ratew ith therouting algorithm of mation?Lveta1．[】examinedtheuniform replicationstrategy random walks．Then a practicable m ethod is proposed to andproportionalreplicationstrategyandfinallyproposedan approach the optimalallocation in the unstructured P2P suboptimalreplication strategy ofsquare·rootreplication to system s．Ourresultsofferanew understandingofreplica- achievetheshorta