14. Microsoft Load Balancing and Clustering

7/31/2019 14. Microsoft Load Balancing and Clustering

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Microsoft Load Balancing and

Clustering


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Outline

Introduction

Load balancing

Clustering


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Introduction

Server cluster is used to provide failover supportfor applications and services.

A Server cluster can consist of several nodes(computers).

Each node is attached to one or more clusterstorage devices.

Cluster storage devices allow different servers toshare the same data, and by reading this dataprovide failover for resources.


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Introduction

Load balancing is used to scale the system

as the client requests are increased

It is suitable for static data which can be

copied to several load balancing servers

Each server is autonomous which means

they dont share any state information


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Cluster Farm

A farm is a group of servers that run similarservices, but do not typically share data.

They are called a farm because they handle

whatever requests are passed out to them usingidentical copies of data that is stored locally.

Because they use identical copies of data (ratherthan sharing data), members of a farm operate

autonomously and are also referred to as clones. Front-end Web servers running Internet

Information Services (IIS) and using NLB are anexample of a farm.


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Cluster Pack

A pack is a group of servers that operate together and share partitioneddata.

They are called a pack because they work together to manage andmaintain services.

Because members of a pack share access to partitioned data, they haveunique operations modes and usually access the shared data on disk

drives to which all members of the pack are connected. An example of a pack is a database Server cluster running SQL Server

2000 and a server cluster with partitioned database views. Members ofthe pack share access to the data and have a unique chunk of data orlogic that they handle, rather than handling all data requests.

In a 4-node SQL Server cluster: Database Server 1 may handle accounts that begin with A-F. Database Server 2 may handle accounts that begin with G-M.

Database Server 3 may handle accounts that begin with N-S.

Database Server 4 may handle accounts that begin with T-Z.


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Server configurations

Server clusters can be setup using many different

configurations.

Servers can be either active or passive, anddifferent servers can be configured to take over the

failed resources of another server.

Failover can take several minutes, depending on

the configuration and the application being used,

but is designed to be transparent to the end-user.


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ClientsWindows Clustering

The Big Picture

IIS Web Serveror other IP based services

Network Load

Balancing

1

2

32

3

4

Data ServersSQL, Exchange, File

Cluster Service


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Clusteringmore detailed picture


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Windows Clustering:Addressing Concerns

Scalability

Scale Up

Scale Out

High Availability

99.9% Uptime

Manageability

Remote

UI and Command line


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Windows ClusteringVocabulary

MSCSServer clusters provide failover of resourcesrepresenting services, applications and base system

features between the servers in the Cluster.

NLB(WLBS) Network Load Balancing clustersdistribute client requests or TCP/IP network traffic

among many servers in the Cluster.

ClusterA group of independent computers that

work together to run a common set of applicationsand provide the image of a single system to the client

and application.

Nodes or HostsEach system in a cluster

confi uration.


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Server ClustersPhysical design

Client PCs

Public network

Private network(heartbeats, status, control)

RAID disk sets

Multi-initiator SCSI orSCSI over Fibre Channel

Cluster servers


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Server ClustersRecommended Environments

Microsoft SQL Server 6.5 & 7.0

Microsoft Exchange 5.5

File shares

Printer shares

Other cluster-aware applications & services

Typical uses are for data that changes

frequently and cannot be easily replicated.


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NLB HostNLB Host

NLB VirtualIP Address

NLB Host NLB Host NLB Host

Internet/

intranet

Network Load BalancingLogical Design

No single point offailure

No performance

bottleneck

No additional hardware

needed

Grow incrementally as

demand increases

Up to 32 nodes in a

cluster

Handle both planned and unplanned server downtime

transparently


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Configuring NLB with two network

adapters 1. Assign appropriate IP addresses to each NIC, placing the NICs in separate

subnets. Rename the first NIC Public and the second to NLB, do this foreach machine.

* Node1

o "Public" NIC* IP address: 10.10.10.11* Subnet: 255.255.255.0* Gateway: 10.10.10.1* DNS: as appropriate

o "NLB" NIC* IP address: 192.168.1.1* Subnet: 255.255.255.0* Gateway: N/A* DNS: N/A

2. On the "Public" NICs, click "Advanced" and add an additional IP address

as the Virtual IP Address which clients will connect to from the Publicnetwork (i.e. - 10.10.10.169)

Node2 -

o "Public" NIC

* IP address: 10.10.10.12

* Subnet: 255.255.255.0

* Gateway: 10.10.10.1

* DNS: as appropriate

o "NLB" NIC

* IP address: 192.168.1.2

* Subnet: 255.255.255.0

* Gateway: N/A

* DNS: N/A


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Infrastructure Scaling


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Clustering on different Windows

versions


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Architecting Multi-node Clusters


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Multiple Sites and Geographically

Dispersed Clusters


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Cluster models

Single node server clusters can be configured with, orwithout, external cluster storage devices. For single nodeclusters without an external cluster storage device, thelocal disk is configured as the cluster storage device.

Single quorum device server clusters have two or morenodes and are configured so that every node is attached toone or more cluster storage devices. The clusterconfiguration data is stored on a single cluster storagedevice.

Majority node set server clusters have two or more nodesbut the nodes may or may not be attached to one or morecluster storage devices. The cluster configuration data isstored on multiple disks across the cluster and the Clusterservice makes sure that this data is kept consistent across

the different disks.


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Cluster application types

Cluster-unaware applications. These types of applications do notinteract with the server cluster at all but can still fail over. Failuredetection is limited. The Cluster service protects these applicationsmainly against hardware failures.

Cluster-aware applications. These types of applications arecharacterized by superior failure detection. The Cluster service canprotect these applications not only against hardware but also againstsoftware failures.

Cluster management applications. These types of applications, whichinclude Cluster Administrator and Cluster.exe, allow administrators tomanage and configure clusters.

Custom resource types. Resource types provide customized clustermanagement and instrumentation for applications, services, anddevices.


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Server cluster components


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References

Microsoft.com

14. Microsoft Load Balancing and Clustering

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