The Impact of Data Center and Server Relocation ... - Network World

A Shunra S<strong>of</strong>tware White PaperFigure 1: A typical regional consolidationBEFOREVancouverTorontoNORTH AMERICASOUTH AMERICALondon HQEUROPEMadridTel AvivPhiladelphiaLos AngelesDallas<strong>Server</strong> to <strong>Server</strong> ConnectionAFTERAFRICAJohannesburgBueno AiresOsloASIA1. Consolidation <strong>of</strong> multiple, small local data centers intolarger regional data centers2. <strong>The</strong> physical move <strong>of</strong> a large central data center to anentirely new locationIn some cases, aspects <strong>of</strong> these two categories may be combinedJAPAN– such as when data centers are both consolidated <strong>and</strong> relocated.<strong>The</strong> principles set forth in this paper are applicable to all suchmoves. Changing the data center’s location directly impacts theway applications are delivered over the network. Users who werepreviously local to front-end applications or back-end infrastructuresuch as policy directories, domain servers <strong>and</strong> other desktop servicesfind that they have become remote users. Because they access thoseservers from a distance, they can potentially experience much longertransaction response times in their business applications as well asfor common tasks such as file copies, desktop boot up <strong>and</strong> login.AUSTRALIAVancouverTorontoNORTH AMERICAPhiladelphiaLos AngelesDallas<strong>Server</strong> to <strong>Server</strong> ConnectionClient to <strong>Server</strong> <strong>Data</strong>SOUTH AMERICABueno AiresFigure 2: A typical relocationLondon HQOsloEUROPEMadridTel AvivAFRICAJohannesburgASIAOn top <strong>of</strong> that, servers that were previously able to support manylocal users completing quick transactions are called upon to supportan increasing JAPANnumber <strong>of</strong> users processing slower transactions dueto added network latency. This has a significant, adverse impact onthe server’s scalability as more <strong>and</strong> more transactions queue up. Inaddition, data center consolidations are <strong>of</strong>ten accompanied by atransition to web-based applications that extend application accessto AUSTRALIAusers across the enterprise, at home <strong>and</strong> on the road. Thus, at thesame time latency <strong>and</strong> scalability issues are introduced, a significantnumber <strong>of</strong> low-b<strong>and</strong>width/high-latency users are also added to analready busy system.BEFOREVancouverTorontoNORTH AMERICAPhiladelphiaLos AngelesDallasClient to server <strong>Data</strong>SOUTH AMERICAOsloLondonEUROPEMadridTel AvivAFRICAJohannesburgASIA<strong>Data</strong> center moves also present a unique challenge because theyexpose users to change. With the deployment <strong>of</strong> new applications,users have no point <strong>of</strong> reference for which to compare applicationperformance.JAPANBut with data center <strong>and</strong> server relocations/consolidations, users immediately notice even small performancedegradations. So any shortcomings in planning <strong>and</strong> managementwill result in immediate complaints from the business, as wellas customers.AUSTRALIA<strong>The</strong> <strong>Impact</strong> on Transaction Response TimeAFTERBueno AiresTorontoVancouverNORTH AMERICAPhiladelphiaLos AngelesDallasClient to server <strong>Data</strong>SOUTH AMERICABueno AiresOsloLondonEUROPEMadridTel AvivAFRICAJohannesburgASIA<strong>Network</strong>-related delays change dramatically during a data centerrelocation, since geographic distance contributes significantly to thenetwork latency between client <strong>and</strong> server. However, in the case <strong>of</strong>data center consolidations, this geographic latency is exacerbated bythe large increase in wide area network (WAN) traffic as more usersaccess servers JAPANremotely.It is a dangerous misconception to equate network latency toapplication latency. <strong>The</strong> fact that 20 200 milliseconds (0.02 – 0.2 <strong>of</strong>a second) are added to the network delay doesn’t mean that theapplication’s latency or response time will only increase by thatAUSTRALIAamount. On the contrary, the relationship between network delay<strong>and</strong> application response time is far from one-to-one. It depends on© 2009 Shunra S<strong>of</strong>tware Ltd. All rights reserved. Shunra is a registered trademark <strong>of</strong> Shunra S<strong>of</strong>tware.