reference architecture dell exchange 2007

8/6/2019 Reference Architecture Dell Exchange 2007

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Dell Exchange 2007Advisor and

RepresentativeDeployments

Product Group - Enterprise

Del l Whit e Paper

By

Farrukh NomanBharath Vasudevan

Apri l 2007


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Conten tsExec ut ive Summary ................................................................................................. 3

In t roduct ion .................................................................................................................. 4

Del l Exc hange 2007 Advisor ............................................................................... 5

Addressing Business Needs............................................................................................ 5

Price versus Performance................................................................................................ 6

Number of Mailboxes ..................................................................................................... 7

Mailbox Size................................................................................................................... 8

Cached Mode .................................................................................................................. 9

Data Availability........................................................................................................... 10

High Availability .......................................................................................................... 11

Hard Drive Speeds........................................................................................................ 12

Storage Topology.......................................................................................................... 13

Tape Backup ................................................................................................................. 15

Anti-Virus / Anti Spam................................................................................................. 16

Additional Exchange Server Roles............................................................................... 17

Exc hange 2007 Reference Arch i t ec t ure .................................................... 18Small Exchange Deployment Up to 500 Users ......................................................... 18

ExchangeServerLayoutRecommendations: .............................................................19Storagerecommendations:........................................................................................20BackupandAvailabilityRecommendations:..............................................................21

Medium Exchange Deployment Up to 1000 Users ................................................... 22


Large Exchange Deployment - Up to 5000 Users ........................................................ 26


Conclusion .................................................................................................................. 31

April 2007 Page 2 Dell Product Group - Enterprise


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Exec ut i ve Summ aryMicrosoftExchangeisoneofthemostpopularandwidelyusedemailapplicationstoday.The

increased companywide reliance upon email for business operations and the individual

requirements

of

users

create

the

need

for

an

e

mail

solution

for

companies

of

all

sizes,

not

just

the

largest corporations. The designed messaging infrastructure should be flexible to meet the

security,availabilityandscalabilityneedsofanorganization.

Inanefforttoreducethecomplexityinchoosingmessagingsolutionsforcompaniesofallsizes,

DellhasperformedextensivetestingandcharacterizationofMicrosoftExchangeServer2007on

standardDellbuildingblocks.ThecollectiveknowledgeearnedthroughDelltestsandlaboratory

experimentsisincorporatedintheDellExchange2007Advisortool.

This paper discusses in detail the sizing features implemented in Dell Exchange 2007 Advisor

Tool and deployment guidance for three Reference architectures of small, medium and large

Exchange environments. The recommended reference architectures for the 3 deployment

scenarios are built on industrystandard Dell components providing secure and available

infrastructuresthatarescalabletoaccommodatefuturegrowthneeds.



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I n t roduc t i onEmail has effectively replaced the telephone as the most essential and important productivity

tool

for

businesses.

Whether

in

the

office

or

on

the

road,

communicating

internally

or

externally

withcustomers,businessusersdependonemailfortheircommunicationneeds.Theincreased

companywiderelianceuponemailforbusinessoperationsandtheindividualrequirementsof

userscreatetheneedforanemailsolutionforcompaniesofallsizes.Suchasolutionshouldbe

less complex to manage and also meet business requirements such as security, regulatory

compliance and availability. Microsoft Exchange Server 2007 incorporates features that enable

businesses to effectively meet those challenges, without fundamentally altering the traditional

methodsusedbyenduserstoaccessemail.

.Thedatafromthecomprehensiveperformancetestsandtheresultingbestpracticesgainedhave

been incorporated in the form of a sizing tool Dell Exchange 2007 Advisor. The following

sectionsof thiswhitepaperexplain theDellExchange2007Advisorandstep through the tool

outputsdesignedforsmall,mediumandlargebusinessneeds.



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Del l Ex c hange 2007 AdvisorTheDellExchange2007Advisorhasbeendesignedasaneasytousetoolthatcancreateadraft

or

general

architecture

for

the

backend

Exchange

infrastructure

while

providing

a

complete

view

ofhardware,software,andservicesofferings thatarerequired tomeetcustomerrequirements.

Theprimarygoalofthistoolistoobtainmessagingrequirementsatacomplexitylevelthatdoes

notrequireITadministratorstoprovideinputs.Throughiteration,customerscanplugdifferent

requirementsintothesizingtoolthemselvesandeffectivelyunderstandthetypeofdeployment

neededpriortocontactingtheiraccountteam.

The following sections elaborate on the Exchange Advisor 2007 input questions that enable

capturingmessagingrequirementsinlesscomplexterms.

Addressing Business Needs

Figure 1:Question1 AddressingBusinessneeds

There

are

many

business

reasons

that

IT

managers

will

choose

to

upgrade

to

or

deploy

Exchange

Server2007.Thesereasonsmayarisefromaneedtoconsolidateserversandstorageortoaddress

security,archiving,compliance,ordisasterrecoveryneeds.ThequestioninFigure1isdesigned

tocapturethoseneedsorissuesthatbusinesseswouldliketoaddresswithExchangeServer2007.

For each of thesebusiness needs, Dell provides a suite of professional services offerings that

includedeployment,migration,andmaintenanceofExchangeServer2007solutions.



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Price versus Performance

Figure 2:Question2 PriceversusPerformance

InadditiontounderstandingthebusinessneedsfordeployingormigratingtoExchangeServer

2007, Dell understands that many different solutions can satisfy a given set of criteria

requirements. Sometimes the need for thebest system performance to effectbest possibleuser

experience can be the business priority, instead of choosing a balanced price/performance

configuration.Somehigherperformancecomponentshaveanaddedpricepremiumassociated

with them, which may notbe necessary for all classes ofbusiness use cases, so a choice to

optimizethesolutionforperformanceorforpriceisoffered.



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Number of Mailboxes

Figure 3:Question3 Numberofmailboxusersandusageprofiles

There are many variables directly related to an end users mailbox that need tobe considered

whendevelopingamessagingsolution.Averagemailboxsizeandnumberofmailboxesaretwo

significantfactors.DellsExchangeAdvisor2007sizingtoolcansizeupto15000mailboxeswith

an average size up to 2GB These are not the only factors for mailbox design that need tobe

understood.Justasimportantasthequantityandsizeofthemailboxesisthenatureoftheusers,

whichcanhavedifferentimpactsonthememory,processoranddiskresourcerequirementofthe

Exchange 2007 environment. Dell has classified Exchange users into three categories: Light,

MediumandHeavyusers.

Lightuserssend5emailsandreceive20emailsinan8hourperiod.

Mediumuserssend10emailsandreceive40emailsinan8hourperiod.

Heavyuserssend20emailsandreceive80emailsinan8hourperiod

TheExchange2007sizingtoolallowscustomerstospecifyatotalof15000usersdistributedover

the threecategories tobetterestimate theprocessor,memoryanddiskrequirementsneeded to

meetthetotaluserneeds.Inadditiontothediskdrivestoragerequiredforhostingmailboxdata,

additionaldiskdrivesarerequiredtohostthetransactionlogs.Transactionlogsarearecordof

messages

sent

and

received,

and

are

used

primarily

to

maintain

consistency

and

to

ensure

the

recoverabilityofmailboxdata.Propercapacityplanningmustaccountfortransactionlogs.

Alongwiththemailboxdataandtransactionlogs,RAIDvolumetypesandperformanceresponse

timeshelpdeterminethediskdrivecountandconfiguration.Bestpracticesdeterminedthrough

Dells characterizationstudies have determined that a RAID 10 oraRAID 1 volume is always

appropriate for hosting the transaction logs. For hosting the mailboxes, the appropriate RAID

typeismoredependentonthenatureoftheusersandtheloadbeingexertedonthemailboxes.If

deploymentsareweightedtowardsheavierloads,RAID10volumesbecomenecessaryduetothe



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demands placed on the physical hard drives. For lighter loads, a RAID 5 implementation can

providethenecessaryperformancewhilerequiringasmallerdiskdrivecountfootprint.

Mailbox Size

Figure 4 Question4:Usermailboxsize

Themailboxsizeisoneofthe important factors inestimating the initialcapacityofthestorage

system

that

will

host

the

mailboxes.

The

mailbox

size

should

be

carefully

chosen

to

satisfy

the

growing needs of the organization. Besides the growing needs of users, the actual mailbox

requires some additional space such as freepages required for database activities, space for

deleted items stored until retention period, space for defragmentation and other NTFS

overheads.Inaddition,if themailbox isalsoenabled forunifiedmessaging,thenextraspace is

requiredtosavevoicemessagesandfaxattachments.

User email mailboxes have evolved tobecome information repositories for the organization,

besides facilitating communications. This raises the need for securing and archiving mailbox

information to meet regulatory compliance and retention requirements. Exchange Server 2007

includes a Messaging Retention Management feature enabling central management of user

personal folders. Also the enhanced and soundjournaling features in Exchange Server 2007

enable suitable archiving solutions within the Exchange infrastructure, or integrating with

WindowsSharepointservicesorwiththirdpartyarchivingsolutions.

This question in Figure 4 enables capturing the organizations mailbox size requirements. The

2048 MB limit in the tool isbased on the currentbest practice trends for mailbox sizes in the

Industry. Exchange Server 2007 can scalebeyond this 2048MB limit specified in the tool for

mailboxsize.Mailboxsizeandusageprofiledeterminethedisksubsystemsizing.Mailboxsize

determinesthediskspacerequirementsand theusageprofiledeterminesdiskI/Operformance



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requirement. Table 1 describes how mailbox characteristics drive storage subsystem disk

requirements.

Mailbox

Characteristics

Light

Usage

Heavy

Usage

Requirement:LowI/OandLessspace Heavy I/O and less

SpaceSmall Mailbox

SizeRecommendation:

Low capacity drives

withRAID5

Low capacity drives

withRAID1/0

Requirement:Low I/O and large

space

Heavy I/O and large

spaceLarge Mailbox

SizeRecommendation:

Large capacity drives

withRAID5

Large capacity drives

with RAID 1/0 or

RAID5

*Choosingbetween 10K or 15K RPM disk drives affect the required number of drives and total cost.Generally10KdrivesarerecommendedforLowI/Oscenariosand15KdrivesforHeavyI/Oscenarios

Table 1 Disksubsystemplanningbasedonmailboxcharacteristics

Cached Mode

Figure 5:Question5 Percentageusersincachedmode



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Thecachedmodeclientsversus theonlinemodeclientsareacrucial factor fordeterminingthe

averageI/Ooperations(IOPS)exertedbythemailboxserveronthedisksubsystem.Thecached

modeOutlookclientsusealocalcopyoftheirmailboxforoperationsandreducetheI/Oloadon

the mailbox server due to local cache access. The online mode clients access the server for all

operationsandincursignificantI/Osonthemailboxserverduetotheirdirectaccesstodisk.The

cachedmodeclientsperiodicallysynchronizewiththemailboxserverinthebackgroundtokeep

themailboxupdated.MoreclientsworkinginonlinemodecauseanincreaseinI/Ooperationson

the mailbox server which in turn requires more diskdrives to satisfy that IOPS requirement.

Therefore,itisnecessarytofindthepercentageofclientsthatcanbeplacedincachemodeversus

onlinemodetodeterminethenumberofdiskdrivesrequiredtosupporttheload.Question5in

Figure 5 helps identify the cached mode versus online mode split to accurately size the disk

subsystem.

Cached mode helps reduce mailbox database I/O operations to disk. Most of this reduction is

realized due to the substantial decrease in database read operations from disk. Due to this

reduction in disk read operations the read/write ratio of Exchangedatabase operations to disk

changeswithcachedmode.Thischangeinread/writeratiotodiskalsohasasignificantimpact

ondisksizingfortheExchangeserver.

Data Availability

Figure 6:Question6 DataAvailability

BusinessContinuityVolumes(BCV)ordiskbaseddatacopiesareanimportantfactortoconsider

while planning for data availability and backups. When the database backup/restore time

duration exceeds thebackup/restore window defined within organizations service agreement,

diskcopiescanbeusedforbackup/restoreinsteadoftapedevices,whicharetraditionallyslow.

Diskcopiesalsoenablequickrecoveryfromdataleveldisasterssuchasusererrors.Datacopies

can be implemented using Local Continuous Replication (LCR) or third party hardware



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mechanisms implemented via Volume Shadow copy Service (VSS). Deployments usually

implement a hybrid solution, utilizing BCV technologies for quick recovery capabilities, and

implementing tapebackup solutions thatback up the BCV data copies to tape for long term

recoveryandarchiving.

LocalContinuous Replication isabuiltin replication technologyavailable inExchange2007 to

createandmaintainacopyof theproductiondatabaseonadifferentsetofvolumeswithinthe

samemailboxserver.VolumeShadowcopyService(VSS)isaWindowsServer2003servicethat

enablesthirdpartymechanismssuchasEMCSnapViewtoprovidehardwarebaseddatacopies

ofapplicationvolumessuchasExchangedatabasevolumes.Thesedatacopiesarehostedona

separate set of disks on the storage system. The question in Figure 6 enables capturing BCV

requirementsforthedeployment.

IfBCVisrequiredforthedeployment,anadditionalsetofdiskdrivesneedstobeplannedinthe

disksubsystemthatwillhostthedatacopiesofExchangevolumes.Theseadditionaldriveswill

bebasedbothonspaceand IOPSrequirementof theBCVsolution.Also theBCV technologies

mayneedadditionalserverresourcessuchasprocessorandmemoryforexecution.

High Availability

Figure 7:Question7HighAvailability

Highavailabilityrefers to improving the uptime of anapplication serviceorsystem for client

access. Application or system downtime periods maybe due to failures or maintenance. High

availability for mailbox server canbe achievedby deploying a cluster using Microsoft Cluster

Services(MSCS).ExchangeServer2007supports two typesofclusteringSinglecopyClusters

(SCC)basedonMSCSsharedstorageclusteringandClusterContinuousReplication(CCR)based

on MSCS Majority Node Set (MNS) replicated storage clustering. The question in Figure 7

capturesthehighavailabilityneedsforthemailboxservers.



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Single copy clusters (SCC) isbased on the MSCS (Microsoft Cluster Service) shared storage

cluster model and manages a single copy of the storage groups and mailbox databases on a

sharedstorage.Itusesclusteredmailboxserversinactive/passivenodeconfigurationconnected

to the shared storage. In the event of a failure on the active server that is serving clients, the

passive server continues hosting the mailbox databases from the shared storage. This type of

clusteringwasalsoavailableinthepreviousversionsofExchangeServer.Localdatacopiesbased

ontheExchangeServer2007LCRfeaturecannotbeenabledonthemailboxserversthatarepart

of the SCC cluster. Cluster continuous replication (CCR) is a new featurebased on the MSCS

MajorityNodeSet(MNS)clustering.ItcombinesthereplicationfeaturesinExchange2007with

failover features in MSCS. A primary server hosts the databases and serves the clients. A

secondary server maintains a copy of the databases and takes over if the primary fails. The

secondary copies are kept consistent and synchronizedby copying and replaying log records

fromtheprimaryserver.Thesecondarycopiesofthedatabasecanbeusedforbackuppurposes

withoutimpactingtheperformanceontheprimaryproductiondatabases.Suchahybridstrategy

canalsoimprovethedurationandfrequencyoftapebackupstrategiesforthesolution.

BothSCCandCCRrequireadditionalserversforthepassiverolesinthecluster.CCRinaddition

requires separate storage disk drives for the secondary copies of the database. Also, if the

secondary database copies are provided on a separate storage system, then CCR can improve

resiliencybyhostingthesecondaryserverandstorageonaseparatedatacenter.

Hard Drive Speeds

Figure 8:Question8 Harddrivespeed

Theselectionofaparticularharddrivespeediscrucialfordeterminingthenumberofdiskdrives

requiredinthestoragesystem.Asdiscussedintheearliersections,bothspacerequirementsand

performancerequirements in termsof IOPSdetermine thenumberofdiskdrives.Themailbox



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server IOPS requirement is determinedby the user profile and number of users. The space

requirementisdeterminedbythemailboxsize,overheadsandnumberofusers.15KRPMdrives

providebetterthroughputthanthe10KRPMdrivesintermsofIOPS.Asageneralruleofthumb,

15KRPMdrivesprovideupto180IOPSand10KRPMdrivesprovideupto120IOPS.Thus,to

supportagivenIOPSworkloadbasedonuserprofiles,fewer15Kdrivesarerequiredthan10K

RPMdrives. The15KRPMdrivesprovidethisimprovedperformanceatahighercostperdrive.

Thedifferencebetweenchoosingthesetwodrivestypesinsmalldeploymentsusingfewdrives

would not be that significant. However, for large database deployments with heavy IOPS

requirements, the 10K RPM drives required willbe extremely costly compared to 15K RPM

drives.Thepricedifferencebecomesasignificantfactorinsuchdeployments.Besidesdrivecosts,

ITshopsalsostandardizeondrive types asabestpractice for management. Generally in such

scenariospreferenceisgivenforonedrivetypeoveranother.

The question in Figure 8 enables capturing the drive type requirements for the deployment.

Generallythenumberof15KRPMdrivesrequiredwillbelesserthan10KRPMdrivestosupport

the workload profiles. The exception to this would be when space requirements warrant

deploying ahigher numberof diskdrives than the IOPS performance requirements and when

10K RPM drives have a higher capacity drive supported than the 15K RPM drives. Such

deploymentsusuallyincludelargemailboxsizeswithlightusagebyusers.

Storage Topology

Figure 9:Question9 StorageTopology

The question in Figure 9 enables capturing the storageattach technology requirements for the

deployment. Usually IT departments standardize or prefer particular attach technology for

externalstorage.DellExchangeAdvisor2007supportsdirectattachedexternalstoragebasedon

SASandFibreChanneltechnologies.ItalsosupportsSANbasedexternalstoragebasedonFibre

Channelforexternalstorage.Choosingonetypeoveranotherisusuallybasedonfactorssuchas



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cost,ease ofmanagement, performance and scalability. DellPowerVault MD1000 isa SAS

based direct attached storage that provides expandability and performance at a low cost. The

Dell|EMC CX320, CX340 and CX380 storage offer flexibility, scalability and performance

coupled with manageability in both SAN attached and direct attached Fibre Channel

configurations.TheTable2showsthesupportedstoragesystemsandtheirfeatures.

StorageSystemsDirect

Attach

SAN

Attach

Attach

Technology

Primary

Drive

Technology

Max. Drive

Speed

(RPM)

Max.

Drives

per

Attach

Dell|EMCCX320 FC FC 15K 120



DellPowerVaultMD1000 SAS SAS 15K 45

*AbovestoragesystemssupportedwithExchange2007AdvisoratthetimeofinitialreleaseinApril2007.

Supported

systems

may

change

in

future

revisions

of

the

tool.

Table 2:ExchangeAdvisor2007supportedstoragesystems

ThestorageperformancerequirementsofadatabaseapplicationlikeExchangeprimarilydepend

on the throughput provided in terms of IOPS. The IOPS throughout is directly related to the

drive speed and number of drives provided. Since Dell PowerVault and Dell |EMC storage

systemssupportboth15Kand10Kdrives,thethroughputperformanceisusuallynotafactorin

choosing the storage. Other factors such as cost, scalability and manageability determine the

choiceofstorage.



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Tape Backup

Figure 10:Question10TapeBackup

Replication technologies discussed in earlier sections provide fastbackup/restore options for

mailbox data and provide continuously updated neartime copy of the running database.

However, theydonotprovidepointintimedatacopies thatspana longerperiodof time.The

regularbackupoptionsprovidepointintimecopies forrecoveringadatabase toanyoldclean

state

and

also

options

for

storing

on

resilient

storage

media

such

as

tapes.

Selecting

a

regular

tape

backup, in addition to the replication and availability methods, is considered abest practice

solution. Tape solutions with largebackup space can retain multiple past pointintime copies

thatspanacrossverylongperiodsoftime. ExchangeServer2007supportsbackingupLCRand

CCRdatacopiesinadditiontoproductiondatabases.Ahybridbackupschemecanbebuiltwith

these options using LCR for daily incrementalbackups and tapebased regularbackup for

weeklyorlongertermdatabackups.



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Anti-Virus / Anti Spam

Figure 11: Question 11 Anti-virus/Anti-spam solution

ThethreatfromvirusesandspamhasbecomeoneofthebiggestconcernsinanyITdeployment

andExchange isnoexception. InExchange2007, theEdgeTransportserverroleprovidesanti

virus/antispamprotectionandfilteringcapabilitiesattheperimeternetwork.Dellalsosupports

SymantecMailSecurityappliancesforantivirus/antispamandcontentfilteringattheperimeter

network. Dell strongly recommends implementing the antivirus/spam solutions to reduce the

amountofunsolicitedemailsandvirusesintheExchangeenvironment.ThequestioninFigure11 enables capturing antivirus/antispam requirements for a deployment. The tool then

appropriatelyrecommendsanantivirus/antispamsolution.



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Additional Exchange Server Roles

Figure 12: Question 12 Additional Exchange Server 2007 Roles

Besides the Mailbox server role, Exchange 2007 includes other server roles to perform various

functions. The Hub Transport server role is required in any exchange2007 deployment and is

responsibleforhandlingallinternalmailflowacrossExchangerolesandappropriatedeliveryof

usermessages.TheClientAccessserverrolehostsservicesandfunctionsrequiredforsupporting

avarietyofmailclientsincludingOutlookWebAccess(OWA)andmobilemessaging. TheEdge

Transport server role sits in the perimeter network and provides functionality for routing

external SMTP mail flow to and from the Internet. The Unified Messaging (UM) server role

providesthenewExchangeServer2007functionalityforintegrationofvoicemailandfaxalong

withemail intousermailboxes.Italsoprovides forOutlookVoiceAccess functionality,which

allowsuserstoaccessemail,voicemail,andcalendarentitiesfromatelephone.

The server roles or a subset of roles canbe consolidated and deployed on the same server

hardware system with a few exceptions. If the Mailbox server is clustered using SCC or CCR,

thennoother role canbe consolidated with it. The EdgeTransport server rolesits outside the

Active Directory framework in the perimeter network and hence cannotbe consolidated with

otherroles.TheHubTransportandClientAccessrolesarerequiredperActiveDirectorysiteinthe organization. Hence when the Mailbox server role is clustered, a separate server system is

required to host these roles. The question in Figure 12 enables capturing the additional role

requirementforadeployment.Thetoolthenrecommendsanappropriateserversystemforeach

oftheadditionalrolefunctionalityselected.

RefertotheDellwhitepapertitledExchangeServer2007DesignConsiderationstolearnmore

aboutExchangeServerrolesandtheirdeploymentconsiderations.



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Exc hange 2007 Reference Arch i t ec t u reThe following sections enumerate three different classes of deployments: small, medium and

large.

The

three

classes

of

users

will

be

characterized

based

on

the

number

and

size

of

mailboxes,

the nature of their use, the size of their deployment, and availability needs. An appropriate

solution willbe presented for each type of deployment with the rationale for the inputs and

explanationoftherecommendedsolution.

Small Exchange Deployment Up to 500 Users

ThefirstreferencearchitecturerepresentsarelativelysmallExchangeorganizationwithupto500

heavyusershavinganaveragemailboxsizeof150MB.Table3summarizestherequirementsfor

thisorganization:

NumberofMailboxes 500

AverageMailboxsize 150MB

UserProfile Heavy

Storage DirectAttachedSAS

DataReplication UsingLCR

HighAvailability None

BackupRequired? Yes

Table 3:SmallExchangeRequirements

Several critical factors must be considered before arriving at a suitable platform for your

Exchangedeployment.Someoftheconsiderationsinclude:

Appropriate server platform with required number of processors, memory and I/O

expandability.

Suitablestoragetechnologywithfuturegrowthandscalabilityinmind.

Highavailabilityrequirements.

Backupmethodology.



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ExchangeServerLayoutRecommendations:Exchange Mailbox/Hub Transport/

ClientAccessServer DellPowerEdge1950

Processors 2xDualCoreIntelXeon

Memory 8GB

NumberofExchangeStorageGroups 4

NumberofExchangeInformationStores 4

SizeofeachExchangeInformationStore 19GB

TapeBackupDrive PowerVault100TLTO3TapeDrive

Table 4:ExchangeServerRecommendationsforSmallExchangeDeploymentAs shown in Table 4 above, a Dell PowerEdge 1950 with two dualcore processors is the

recommended server platform for this environment. The Mailbox, Hub Transport and Client

Accessserverrolescanbeconsolidatedon thesamephysicalserver.TheDellPowerEdge1950

has sufficient processing capability to handle the Mailbox services and all the message

transportationservicesrequiredbyotherserverroles.

IftheUnifiedMessagingserverroleorEdgeTransportserverroleisrequired,additionalphysical

serversmayberequired.IftheEdgeTransportserverisnotapartoftheorganization,thenthe

Hub Transport server canbe configured to relay Internet messages. This deployment assumes

thattheMailboxserverisnotdeployedinahighlyavailable(HA)clusteredenvironment.IfHA

isrequiredfortheMailboxserverroleusingSingleCopyClusters(SCC)orClusterContinuous

Replication(CCR),nootherrolecanbeconsolidatedwiththeMailboxroleonthesameserver.



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Figure 13:SmallExchangeArchitecturewithLCRDeployment

Based on the user load, the minimum memory required for the Exchange server is 8 GB. This

amountofmemorywillbesuitableforservingfourstoragegroupsandadditionalRAMmaybe

requiredforsupportingmorestoragegroups.

Storagerecommendations:ThefollowingarethestoragerecommendationsusingRAID10forExchangeinformationstores:

StorageSystem DellPowerVaultMD1000

Totalnumberofdrives 10

Totalnumberofenclosures 1

DrivesforExchangeInformationStores 4x73GB15KSASusingRAID10

DrivesforTransactionLogs 2x36GB15KSASusingRAID1

DrivesforLCR 3x300GB15KSASusingRAID5

Numberofdrivesforhotspare 1x300GB15KSAS

Table 5:

Storage

Recommendations

for

Small

Exchange

Deployment

Using

RAID

10



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ThefollowingarethestoragerecommendationsusingRAID5forExchangeinformationstores:






DrivesforLCR 3x300GB15KSASusingRAID5


Table 6:StorageRecommendationsforSmallExchangeDeploymentUsingRAID5Several factors are considered while determining the type and capacity of the storage system.

DatabaseLUNcapacitydependsonthemailboxquotaaswellassomeotherfactorssuchasthe

whitespaceorfreepagesrequiredbythedatabase,spacefordeleteditemsstoreduntilretention

period, space for defragmentation and other NTFS overheads. Log LUN capacity depends on

how far in thepast the logsshouldbebackedup orreplayed torestoredatabase designof an

organization.Additionally,ExchangeisanI/Ointensiveapplicationandallclientactivitycauses

updates to theExchangedatabase,whichproduces I/Ooperations todisk.Thedisksubsystem

shouldbe capable of meeting these demands. It is therefore important to size the disks for

performanceandnotjustforcapacityofthemailboxes.

Basedonthesefactorstwostoragerecommendationsarepresented:usingRAID10andRAID5

forExchange informationstore.RAID10offers thebestperformancewithhighprotection,but

only50%oftheRAIDgroupcapacityisusable.RAID5offersahigherusablecapacityperRAID

groupthanRAID10.Itcanbeeffectiveforenvironmentswithverylargemailboxesand/orlower

IOPSrequirements.

Considering the capacity and IOPS requirements for this environment, the Dell PowerVault

MD1000isasuitablestorageplatform.Thisarrayutilizesenterpriseclasstechnologywithhigh

performancedrivesthataresuitableforExchangeworkloads.Itprovidesbalancedcapacityand

excellentI/Operformancewith10Kand15KRPMSASdrives.

Table5andTable6explainthedriveconfigurationsfortheRAID10andRAID5solutions.

BackupandAvailabilityRecommendations:To achieve mailbox resiliency, at a minimum Dell recommends using Local Continuous

replication(LCR)toreducetherecoverytimefordataleveldisasters.LCRmaintainsalocalcopy

ofthemailboxdatabaseontheMailboxserverandkeepsthecopyconsistentwiththeproduction

databaseby replaying log records on them. The database copies canbe manually switched to

function as production databases during failures or during maintenance. For a Mailbox server

enabled forLCRoperation,additionalhardwareresourcesarerequired tostore theproduction

data and handle LCR related IOPS load. The majority of the additional resource consumption

comes from log updates through reads and writes on the passive copy. For this reference

architecture,theabovementionedprocessorsandmemoryrecommendationsforthePowerEdge



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server shouldbe sufficient to implement LCR. However, the storage system would require

additionaldrivestostorethepassivecopyofproductionLUNs.AsshowninTable5andTable6,

three300GB,15KRPMSASdrivesconfiguredusingRAID5isrequiredforthepassivecopy.

Even though Local Continuous Replication provides a level of protection for mailbox data, it

cannotreplacetheregulardatabasebackupbecauseitonlyprovidescontinuouslyupdatednear

timecopyof theactivedatabase.Regularbackupoptionsprovidepastpointintimecopies for

recoveringadatabasetoanyoldcleanstate.ThepassiveLCRcopycanbeusedasthesourcefor

backup. This can reduce the impact of the backup operation on the active database. Dell

recommends using PowerVault 100T LTO3 tape drive, which has a maximum capacity of

400GBandmaximumbackupspeedof243GB/hour.

Medium Exchange Deployment Up to 1000 Users

ThemediumsizeExchangereferencearchitecturerepresentsanExchangeorganizationwithup

to

1000

heavy

users

having

an

average

mailbox

size

of

250

MB.

As

the

number

of

users

increases,

themessaginginfrastructureneedstogrowtosupporttheadditionalworkloadsandfeatures.

Table7summarizestherequirementsforthisorganization:


AverageMailboxsize 250MB

UserProfile Heavy

Storage DirectAttachedSAS

HighAvailability UsingCCR

BackupRequired? Yes

Table 7:MediumExchangeRequirements



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ExchangeServerLayoutRecommendations:ExchangeMailboxPrimarysite DellPowerEdge1950


Memory 8GB

ExchangeMailboxSecondarysite DellPowerEdge1950


Memory 8GB

ExchangeHub/CASServer DellPowerEdge2950


Memory 8GB




Table 8:ExchangeServerRecommendationsforMediumExchangeDeployment

As shown in Table 8 above, the following are the recommended server platforms for this

referencearchitecture:

ExchangeMailboxServer:

- DellPowerEdge1950withtwodualcoreprocessors

- 8GBRAM

ExchangeHubTransport/ClientAccessServer:


- 8GBRAM



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Figure 14:MediumExchangeArchitecturewithCCRDeployment

If Unified Messaging or Edge Transport server roles are required, additional physical servers

maybe required. If the Edge Transport Server is not a part of the organization, then the Hub

TransportservercanbeconfiguredtorelayInternetmessages.

This reference architecture includes Cluster Continuous Replication (CCR). CCR isbased on

MSCSMajorityNodeSet(MNS)clustering,whereinacopyofthemailboxdatabasesishostedon

anotherserverwith itsownstoragespace.Mailclientsaccess theprimaryserver,anddatabase

changes to it are shipped to the secondary server in the form of log records. The shipped log

recordsareplayedonthesecondaryservertokeepthesecondarydatabasecopiesconsistentwith

the primary. If the primary Mailbox server fails, the MNS clustering mechanism automatically

promotes the secondary server to start serving the clients. CCR providesboth mailbox high

availabilityandalsositerecoverythroughhostingthesecondaryserveronaseparatedatacenter.

SinceCCRisusedforhighavailability,nootherExchangeserverrolecanbeconsolidatedwith

theMailboxroleonthesameserver.ThereforetheHubandCASserverroleshavebeensplittoa

separateserver.TheDellPowerEdge2950withtwodualcoreIntelXeonprocessorsand8GBof

RAMisasuitableplatformfortheseroles.



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Storagerecommendations:The following is the storage recommendations for the primary CCR site using RAID 10 for

Exchangeinformationstores:







Table9:StorageRecommendationsforMediumExchangeDeploymentUsingRAID10

Anidenticalstorageconfigurationwith13drivesisrequiredforthesecondaryCCRsite.

The following is the storage recommendations for the primary CCR site using RAID 5 for

Exchangeinformationstores:







Table10:StorageRecommendationsforMediumExchangeDeploymentUsingRAID10

Anidenticalstorageconfigurationwith15drivesisrequiredforthesecondaryCCRsite.

Two storage recommendations are presented: using RAID 10 and RAID 5 for Exchange

informationstore.RAID10offersthebestperformancewithhighprotection,butonly50%ofthe

RAID group capacity is usable. RAID 5 offers a higher useable capacity per RAID group than

RAID 10. It canbe effective for environments with very large mailboxes and/or lower IOPS

requirements.

Considering the capacity and IOPS requirements for this environment the Dell PowerVault

MD1000isasuitablestorageplatform.Thisarrayutilizesenterpriseclasstechnologywithhigh

performancedrivesthataresuitableforExchangeworkloads.ItprovidesbalancedcapacityandexcellentI/Operformancewith10Kand15KRPMSASdrives.

Table9andTable10explainthedriveconfigurationsfortheRAID10andRAID5solutions.



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BackupandAvailabilityRecommendations:Deploying a high availability solution for database related applications is always considered a

bestpracticetoavoidfailurescenarios.DellrecommendsusingCCRtoensureapplicationaswell

asdataavailability.To implementCCR,asecondarysitewithstorageandserverconfiguration

identical to the primary Exchange Mailbox server is required. Figure 14 shows a passive

ExchangeMailboxserverandstoragesystemallocatedforCCR.

TapeBackup PowerVaultTL4000TapeLibrary

TapeBackupserver PowerEdge1950


Servermemory 4GB

Table5:TapeBackupRecommendationsforMediumExchangeDeployment

Additionally,PowerVaultTL4000tapebackuplibraryisrecommendedtocreatepointintime

backups of the Exchange server data. The tape library attaches to a separate PowerEdge 1950

serverknownasthebackupserver.ThebackupserverconnectstotheExchangeserversoverthe

LANtoconductthebackup.Thiscentralizedapproachhelpssimplifybackupadministration.

Large Exchange Deployment - Up to 5000 UsersAs a messaging infrastructure grows in size, it typicallybrings more complexity. The

message routing services and policies overhead increases and requires more hardware

resources to satisfy the growingbandwidth requirements. The large Exchange reference

architecture represents an Exchange organization with up to 5000 heavy users having an

averagemailboxsizeof1GB.Table12summarizestherequirementsforthisorganization:


AverageMailboxsize 1GB

UserProfile Heavy

Storage SANAttachedFiberChannel

HighAvailability UsingSCC

BackupRequired? Yes

Table 12:LargeExchangeRequirements



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ExchangeServerLayoutRecommendations:PowerEdge6950or

ExchangeMailboxActivePowerEdge6850

4xDualCoreAMDOpteronor


Memory 32GB

PowerEdge6950orExchangeMailboxActive

PowerEdge6850

4xDualCoreAMDOpteronorProcessors

4xDualCoreIntelXeon

Memory 32GB

ExchangeHubTransportServer DellPowerEdge2950


Memory 6GB

ExchangeCASServer DellPowerEdge2950


Memory 4GB




Table 13:ExchangeServerRecommendationsforLargeExchangeDeployment

As shown in Table 13 above, the following are the recommended server platforms for this

referencearchitectureare:

ExchangeMailboxServer:

- DellPowerEdge6950orDellPowerEdge6850withfourdualcoreprocessors

- 32GBRAM

ExchangeHubTransportServer:


- 6GBRAM

ExchangeCASServer:


- 4GBRAM

For a large number of mailboxes, thebest practices involve scaling out all the Exchange

server roles on separate servers. The physical separation of the server roles will provide

better utilization of resources and good performance. Another reason for separating the

Mailbox server is to allow implementing highavailability clustering option using Single



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Copy clusters (SCC). SCC isbased on Microsoft Cluster Services (MSCS) shared storage

clustering, wherein a single copy of the databases resides on a shared external storage

connectedtotwoMailboxservernodes.Oneoftheservernodes,calledtheactivenode,

hoststhemailboxdatabasesandservestheclients.Iftheactivenodeincursafailure,the

other node, called the passive node, takes over hosting mailbox databases from the

sharedstorageandcontinuesservingtheclients.

Figure 15:LargeExchangeArchitecturewithSCCDeployment



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Storagerecommendations:ThefollowingarethestoragerecommendationsusingRAID10forExchangeinformationstores:

StorageSystem Dell|EMCCX320


Totalnumberofdiskarrayenclosures 6

DrivesforExchangeInformationStores 60x300GB10KFCusingRAID10

DrivesforTransactionLogs 18x73GB10KFCusingRAID10

Numberofdrivesforhotspare 3x300GB10KFC

StorageOSdrives 5x73GB10KFC

Table 14:StorageRecommendationsforLargeExchangeDeploymentUsingRAID10

ThefollowingarethestoragerecommendationsusingRAID5forExchangeinformationstores:

Storage

System

Dell|EMC

CX3

20


Totalnumberofdiskarrayenclosures 7

DrivesforExchangeInformationStores 70x300GB10KFCusingRAID5

DrivesforTransactionLogs 18x73GB10KFCusingRAID10

Numberofdrivesforhotspare 3x300GB10KFC

StorageOSdrives 5x73GB10KFC

Table 15:StorageRecommendationsforLargeExchangeDeploymentUsingRAID5

Two storage recommendations are presented: using RAID 10 and RAID 5 for Exchange

informationstore.RAID10offersthebestperformancewithhighprotection,butonly50%ofthe

RAID group capacity is usable. RAID 5 offers a higher usable capacity per RAID group than

RAID 10. It canbe effective for environments with very large mailboxes and/or lower IOPS

requirements.

ConsideringthecapacityandIOPSrequirementsforthisenvironmenttheDell|EMCCX320isa

suitable storage platform which can support for up to 120 FC drives. Table 14 and Table 15

explainthedriveconfigurationsfortheRAID10andRAID5solutions.

BackupandAvailabilityRecommendations:ImplementingSingleCopyCluster (SCC)willrequireanadditionalPowerEdge6850or6950

serverwithsamehardwareconfigurationas theactiveMailboxserver.Theadditional installed

server acts as the passive Mailbox server and shares the same storage system with the active

Mailbox server. In the event of a failure on the active mailbox server, the Exchange Mailbox

serverrolefailsovertothepassivenodeandresumesactivity.



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TapeBackup PowerVaultML6030CMLibrary

TapeBackupserver PowerEdge2950


Servermemory 4GB

Table 16:TapeBackupRecommendationsforLargeExchangeDeployment

For thisenvironment, thePowerVaultML6030CMLibrary is therecommended tapebackup

device. Additionally, the Dell PowerEdge 2950 maybe used as the tapebackup server. The

backup server connects to the Exchange serversover the LAN or SAN to conduct thebackup.

Thiscentralizedapproachhelpssimplifybackupadministration.ThenetworktopologyforSAN

basedbackupsisdesignedtoimproveapplicationperformancebecauseitisroutedoverahigh

speedFibreChannelnetwork.



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ConclusionInmessagingdeploymentswithExchangeServer2007,therearemanydifferentcriteriathatcan

affect

how

servers

and

storage

need

to

be

sized.

These

factors

impact

memory,

processor

and

diskutilizationandcanvarygreatlyfromoneimplementationtothenext.Becauseofthework

performed at Dell Labs to actively characterize the Mailbox role of Exchange Server 2007 on

Dells enterprise server and storage portfolio, Dell is able to provide deployment

recommendations. In order to make those recommendations accessible to customers, Dell

developedtheonlineExchange2007AdvisorTool.Thediscussionaboutthetooloutputforthe

three defined reference architectures was intended to provide an insight into how the

recommendationsarecalculated.Tocalculatetherequirementsforanyconfiguration,thetoolcan

beaccessedathttp://www.dell.com/exchange.

THIS WHITE PAPER IS FOR INFORMATIONAL PURPOSES ONLY, AND

MAY CONTAIN TYPOGRAPHICAL ERRORS AND TECHNICAL

INACCURACIES. THE CONTENT IS PROVIDED AS IS, WITHOUT EXPRESSOR IMPLIED WARRANTIES OF ANY KIND.

Dell Inc. 2007. All rights reserved. Dell, PowerEdge, PowerVault, and the Dell

logo are trademarks of Dell Inc. Microsoft is a registered trademark of Microsoft

Corporation. Other trademarks and trade names are the property of their

respective owners and Dell disclaims proprietary interest in the marks and names of

others.
http://www.dell.com/exchangehttp://www.dell.com/exchange

reference architecture dell exchange 2007

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