Building Scalable and Building Scalable and Reliable Web ApplicationsReliable Web Applications

Vineet GuptaVineet GuptaTechnology EvangelistTechnology EvangelistMicrosoft CorporationMicrosoft Corporation

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AgendaAgenda

IIS 6.0 and ASP.Net ArchitectureIIS 6.0 and ASP.Net Architecture

ReliabilityReliability

State ManagementState Management

CachingCaching

Other Cool StuffOther Cool Stuff

AgendaAgenda

IIS 6.0 and ASP.Net ArchitectureIIS 6.0 and ASP.Net Architecture

ReliabilityReliability

State ManagementState Management

CachingCaching

Other Cool StuffOther Cool Stuff

DLLHost.EXE

ISAPIExtensions

DLLHost.EXE

ISAPIExtensions

Rearchitecting IISRearchitecting IISA review of IIS5A review of IIS5

TCP/IPkernel

user WinSock 2.0

INETINFO.EXE

Metabase

ISAPI Filters and Extensions DLLHost.EX

E

ISAPIExtensions

INETINFO.EXE

MetabaseMetabase

ISAPI Filters and Extensions

web web appapp

IIS 6.0 ArchitectureIIS 6.0 Architecture

Goal: Enable complete app Goal: Enable complete app isolation from other Web isolation from other Web apps and core Web serverapps and core Web server

Web service in INETINFO Web service in INETINFO split out to do this:split out to do this:

Http.sys: Kernel mode Http.sys: Kernel mode listener and request routerlistener and request router

WAS: Config and process WAS: Config and process managermanager

W3wp.exe: Where Web apps W3wp.exe: Where Web apps are processedare processed

Multiple W3wp.exe filesMultiple W3wp.exe files

WASWASW3wp.exeW3wp.exe

web web appapp

Http.sysHttp.sys

Ker

nel

Ker

nel

W3wp.exeW3wp.exe

web web appapp

W3wp.exeW3wp.exe

Web Web AppApp

Process Model ContrastProcess Model Contrast IIS5 to IIS6 – Making it more robustIIS5 to IIS6 – Making it more robust

HTTP.SYSHTTP.SYSHTTP.SYSHTTP.SYS TCP/IP TCP/IP ConnectionsConnections

RequestsRequests

User Mode

Kernel Mode

App2App2

FiltersFilters

Worker Worker ProcessProcess

App2App2

FiltersFilters

Worker Worker ProcessProcess

App1App1

FiltersFilters

Worker Worker ProcessProcess

WASWASWASWAS

INETINFOINETINFO

metabasemetabase

AppPool 1AppPool 1 AppPool 2AppPool 2

ASP.Net on IIS 6ASP.Net on IIS 6.NET Application Domains vs. Application Pools.NET Application Domains vs. Application Pools

Application domainsApplication domainsLightweight CLR unit of isolationLightweight CLR unit of isolation

One app domain per IIS applicationOne app domain per IIS application

Combine with W3wp.exe files to Combine with W3wp.exe files to achieve high scalability and isolationachieve high scalability and isolation

ASP.NET manages app domains ASP.NET manages app domains independentlyindependently

Recycled within a single processRecycled within a single process

Can have private components, Can have private components, session variables , etc.session variables , etc.

Http.sysHttp.sys

W3wp.exeW3wp.exe

ASP.NETASP.NETWASWAS

App poolApp pool

W3wp.exeW3wp.exe

ASP.NETASP.NET

AppApp

DomainDomainAppApp

DomainDomainAppApp

DomainDomainAppApp

DomainDomainAppApp

DomainDomainAppApp

DomainDomainAppApp

DomainDomainAppApp

DomainDomain

Application PoolApplication Pool

W3wp.exeW3wp.exe

ASP.NETASP.NET

App poolApp pool

DemoDemoApplication PoolsApplication Pools

AgendaAgenda

IIS 6.0 and ASP.Net ArchitectureIIS 6.0 and ASP.Net Architecture

ReliabilityReliability

State ManagementState Management

CachingCaching

Other Cool StuffOther Cool Stuff

Application PoolsApplication PoolsApplication Isolation in ProcessesApplication Isolation in Processes

Can create 1 or more Can create 1 or more application poolsapplication pools

Each served by 1 or Each served by 1 or more processes.more processes.

Each worker process Each worker process serves only 1 pool.serves only 1 pool.

Reqs routed directly to Reqs routed directly to pool by HTTP.syspool by HTTP.sys

Isolate apps based Isolate apps based on:on:

Site/CustomerSite/Customer

FunctionalityFunctionality

ReliabilityReliability

RecyclingRecyclingWhat is it and Why use it?What is it and Why use it?

What is it?What is it?Periodically restart Periodically restart applications based on:applications based on:

UptimeUptime# of requests# of requestsScheduled timeScheduled timeMemory consumptionMemory consumptionOn-demandOn-demand

Why use it?Why use it?Refresh apps to ensure Refresh apps to ensure availabilityavailabilityPrevent bad apps from Prevent bad apps from taking over the systemtaking over the system

No interruption in No interruption in Service!!Service!!

RecyclingRecyclingOverlapping RecycleOverlapping Recycle

kernel

user

WA

SW

AS

HTTP.SYSHTTP.SYS

Old Old Worker Worker ProcessProcess

ISAPI Exts &ISAPI Exts &FiltersFilters

Web Proc. Web Proc. Core DLLCore DLL

Ready for Ready for

RecycleRecycle

New New Worker Worker ProcessProcess

ISAPI Exts &ISAPI Exts &FiltersFilters

Web Proc. Web Proc. Core DLLCore DLL

Shut downShut down

RequestRequest

startupstartupreadyready

RequestRequest

DemoDemoProcess RecyclingProcess Recycling

AgendaAgenda

IIS 6.0 and ASP.Net ArchitectureIIS 6.0 and ASP.Net Architecture

ReliabilityReliability

State ManagementState Management

CachingCaching

Other Cool StuffOther Cool Stuff

Increasing .NET Scale & PerformanceIncreasing .NET Scale & PerformanceAttributes of Scalable Web ApplicationsAttributes of Scalable Web Applications

StatelessStatelessApplication code and components can be Application code and components can be restarted cheaply; session state is restarted cheaply; session state is managed externally in some sort of state managed externally in some sort of state storestore

Low initialization costsLow initialization costsApplications should avoid doing heavy Applications should avoid doing heavy processing at startup or assume that they processing at startup or assume that they will run for a long timewill run for a long time

Increasing .NET Scale & PerformanceIncreasing .NET Scale & PerformanceAttributes of Scalable Web ApplicationsAttributes of Scalable Web Applications (2) (2)

Can have multiple instancesCan have multiple instancesAll the components and classes of an All the components and classes of an application should be able to have multiple application should be able to have multiple instances in separate processes without instances in separate processes without namespace or locking issuesnamespace or locking issues

Expect administrator-imposed limitsExpect administrator-imposed limitsYour application is likely to haveYour application is likely to have

CPU limitsCPU limitsMemory limitsMemory limitsProcessor affinity imposedProcessor affinity imposed

Making Applications More ReliableMaking Applications More Reliable

Web Farm Session StateWeb Farm Session State

Session state can be stored in an external Session state can be stored in an external processprocess

ASPState Service ASPState Service MicrosoftMicrosoft®® SQL Server SQL Server™™ 2000 2000

Big reliability wins Big reliability wins Session state survives crashes/restartsSession state survives crashes/restarts

Enables Web farm deploymentEnables Web farm deploymentSession state can now be shared across a Web Session state can now be shared across a Web farm of ASP.NET serversfarm of ASP.NET serversApplications no longer tied to one computerApplications no longer tied to one computer

Design your apps to be recycled!Design your apps to be recycled!

DemoDemoManaging StateManaging State

AgendaAgenda

IIS 6.0 and ASP.Net ArchitectureIIS 6.0 and ASP.Net Architecture

ReliabilityReliability

State ManagementState Management

CachingCaching

Other Cool StuffOther Cool Stuff

Dynamic Kernel CachingDynamic Kernel Caching

Cache

Network Stack

HTTP.SYS

W3WP.EXE (IIS6.0)

ASP.NET/CLR

User Application

UserKernel

Database

RequestRequest ResponseResponse

WithoutWithoutCacheCache

Cache

Network Stack

HTTP.SYS

W3WP.EXE (IIS6.0)

ASP.NET/CLR

User Application

UserKernel

Database

WithWithCacheCache

RequestRequest ResponseResponse

ASP.Net 2.0 Caching ImprovementsASP.Net 2.0 Caching ImprovementsData CachingData Caching

Data-set based data-sources can be Data-set based data-sources can be easily cachedeasily cached

Just set EnableCaching to true on data-Just set EnableCaching to true on data-source controlsource control

Also set CacheDuration, CacheExpirationPolicyAlso set CacheDuration, CacheExpirationPolicy

SQL Cache Invalidation for Stale DataSQL Cache Invalidation for Stale DataSQL 7, 2000 use a custom change table, a SQL 7, 2000 use a custom change table, a DB trigger and a polling mechanism by DB trigger and a polling mechanism by ASP.NetASP.Net

SQL 2005 uses Service BrokerSQL 2005 uses Service Broker

ASP.Net 2.0 Caching ImprovementsASP.Net 2.0 Caching ImprovementsPost-Cache Substituion Post-Cache Substituion

Output Cache an entire page except XXXOutput Cache an entire page except XXXXXX must be a simple stringXXX must be a simple string

Use Response.WriteSubstitution with Use Response.WriteSubstitution with callbackcallback

Or Use Substitution Control with Or Use Substitution Control with associated Callback methodassociated Callback method

DemoDemoCachingCaching

AgendaAgenda

IIS 6.0 and ASP.Net ArchitectureIIS 6.0 and ASP.Net Architecture

ReliabilityReliability

State ManagementState Management

CachingCaching

Other Cool StuffOther Cool Stuff

Resource Optimization in IIS 6Resource Optimization in IIS 6Idle Timeout and Demand StartIdle Timeout and Demand Start

Idle timeoutIdle timeoutTimeout and shutdown idle processes if process Timeout and shutdown idle processes if process is idle for given period of time.is idle for given period of time.Frees resources for active applications.Frees resources for active applications.Apps still available even if worker process idles Apps still available even if worker process idles out and is shut down! out and is shut down!

Demand startDemand startOnly start worker process if there is demand for Only start worker process if there is demand for the application pool. the application pool.

Application considerationsApplication considerationsUse idle timeout to free up resources for other Use idle timeout to free up resources for other heavy-use applications.heavy-use applications.Consider disabling idle timeout if starting an Consider disabling idle timeout if starting an application takes a long time.application takes a long time.

View State ImprovementsView State Improvements

More efficient More efficient serialization format serialization format reduces state sizereduces state size

Splitting View State Splitting View State into Control State into Control State and UI Stateand UI State

Site CompilationSite Compilation

Pre-Compile your websitePre-Compile your websiteUse aspnet_compiler.exeUse aspnet_compiler.exe

Endpoints reduced to empty files Endpoints reduced to empty files (aspx)(aspx)

No request-time compilationNo request-time compilation/bin contains compiled assemblies for /bin contains compiled assemblies for entire siteentire site

DemoDemoCool Stuff Cool Stuff

AgendaAgenda

IIS 6.0 and ASP.Net ArchitectureIIS 6.0 and ASP.Net Architecture

ReliabilityReliability

State ManagementState Management

CachingCaching

Other Cool StuffOther Cool Stuff

RecommendationsRecommendations

Move to IIS 6 and ASP.Net 2.0Move to IIS 6 and ASP.Net 2.0

Design Apps for RecyclingDesign Apps for Recycling

Design Stateless AppsDesign Stateless AppsOr think out-of-proc state managementOr think out-of-proc state management

Use Caching wherever you can!Use Caching wherever you can!

Questions?Questions?

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