MVA Jump Start

Module 10

High Availability in Lync Server 2013

Module Overview

• High Availability in Lync Server 2013

• Configuring High Availability in Lync Server 2013

• Planning for Load Balancing

• Designing Load Balancing

Lesson 1: High Availability in Lync Server 2013

• Resiliency and High Availability

• Front End Pool Architecture

• Back End Server High Availability

• File Sharing High Availability

• Persistent Chat High Availability

Resiliency and High Availability

Resiliency High Availability

A manual disaster recovery process used to recover

from a complete site failure.

You can configure your unified communications

solution for high availability and enable site

resilience by using the functionalities and features

of Lync Server 2013

A service or system designed in such a manner that

it is intended to be available to its users

continuously, with only minimal scheduled or

unscheduled unavailability because of planned

maintenance or outages

Resiliency makes high availability possible. Lync Server 2013 supports

deployment of one or more sites that can be scaled to meet high

availability and location requirements

You can structure these sites and their components to meet the

access and resiliency requirements of your organization

Front End Pool Architecture

New Distributed Systems Architecture

• Back End Database no longer the real-time data store

•User information kept on up to three Front End Servers

•Data distribution is automatic

• Enterprise Pools

• Recommend a minimum of 3 servers in a pool

• Thresholds for pool functionality

Back End Server High Availability

•Deploy Two Back End SQL Servers for a single Pool

• Synchronous SQL Mirroring

•Recovery Time = 5 minutes

•User Experience depends on optional Witness

Principal SQL

Server (DB1)

Mirror SQL

Server (DB1)Lync Server 2013

Pool (EE)

Witness SQL

Server

SQL Transaction SQL Data Flow

File Sharing High Availability

Distributed File System

• Failover from one file server to another

• Based on network size/resiliency level:

• One pair for all file shares in a site

• One pair per Front End Pool

• Best Effort Replication

• For critical data, continue backups frequently

Persistent Chat High Availability

•Multiple Server Pool

• Up to 8 total servers (max 4 active)

• Back End High Availability can be used

• SQL Mirroring

• Stretched Pool available for Disaster Recovery

Lesson 2: Configuring High Availability in Lync Server 2013

•Configuring Back End High Availability

•Deploying Enterprise Edition Pools

Configuring Back End High Availability

Requirements for SQL Mirroring include:

• Primary, Mirror and Witness must use same SQL Version

• Primary and Mirror must use same SQL Edition

• Witness can be different edition

• Instances names do not need to match

• Recommended to have names match

Configuration and Management:

• Defined in Topology Builder or Lync Management Shell

• Publishing deploys SQL mirroring automatically

• Can be configured for new or existing pools

• Mirror Change/Removal

• Uninstall-CSMirrorDatabase, Topology Builder

Deploying Enterprise Edition Pools

Deployment Planning includes:

• Recommend three servers minimum

• Two Server Enterprise Pool Guidelines

Pool Management includes:

• Ensure required number of servers are running

•Adding/Removing Front End Servers to a Pool

• Must restart each Front End (one at a time)

Lesson 3: Planning for Load Balancing

•DNS and Hardware-Based Load Balancing

• Planning for Load Balancing Infrastructure Components

• Planning for Coexistence

DNS and Hardware-Based Load Balancing

Lync Server 2013

DNS Load BalancingHardware Load Balancing

Planning for Load Balancing Infrastructure Components

• Plan for keeping all Front End Servers in the Lync Server 2013 pool

operational

• Plan for identifying the components that do not support load

balancing and work on mitigation strategies

• Plan for using hardware devices that have firmware updates to

support DNS load balancing

• Plan for migrating previous versions of servers and clients to Lync

Server 2010/2013

Planning for Coexistence

Hardware

Load Balancing

Office Communication Server R2 Clients

DNS Load

Balancing

Lync Server 2010/2013 Clients

Lync Server 2013

Lesson 4: Designing Load Balancing

•Designing DNS-Based Load Balancing

•DNS Load Balancing Requirements

•Designing Hardware-Based Load Balancing

•Hardware Load Balancing Requirements

•Designing Servers and Services for Load Balancing

•Guidelines for Deploying DNS Load Balancing for Front End Server

Pool

•Designing a Coexistence Strategy

Designing DNS-Based Load Balancing

Lync 2013 Client

Hardware Load Balancer

(for web traffic)

VIP: 10.10.0.99

Lync Server 2013 Enterprise Pool

Pool Name: pool.adatum.com

Front End Server: van-fe01.adatum.com (10.10.0.20)

Front End Server: van-fe02.adntum.com (10.10.0.30)

1: DNS load balancing-aware client

resolves SRV record and queries for IP

address for pool.adatum.com

2: DNS returns all A records for

pool.adatum.com: 10.10.0.20 and

10.10.0.30

3: Client initiates connection to random

Front End Server

3

DNS Server

DNS Load Balancing Requirements

DNS load balancing is supported for the following:

• Front End pools

• Edge server pools

•Director pools

• Standalone Mediation server pools

Prerequisites for using DNS load balancing:

•Override the internal Web services pool FQDN

• Create DNS A host records to resolve the pool FQDN to IP addresses of all the servers in the pool

Designing Hardware-Based Load Balancing

DNS Server

Hardware Load Balancer

VIP: 10.10.0.99

Lync Server 2013 Enterprise Pool

Pool Name: pool.adatum.com

Front End Server: van-fe01.adatum.com (10.10.0.20)

Front End Server: van-fe02.adatum.com (10.10.0.30)

1: Client resolves SRV record and

queries for IP address of

pool.adatum.com

2: DNS returns VIP of hardware load

balancer:10.10.0.99

3: Client initiates connection to

hardware load balancer

3

Lync 2013 Client

Hardware Load Balancing Requirements

Prerequisites for hardware load balancers include:

•Must be a hardware load balancer

•Must expose a VIP address through ARP

•Must allow multiple ports to be open at the same time

• The load balancer provides TCP-level affinity

Infrastructure requirements:

• The VIP must have a single DNS entry

• The VIP must be a static IP address

• The Lync server must have a registered FQDN

• The network adapter must have exactly one IP address

Designing Servers and Services for Load Balancing

Criteria for deciding the servers or services that need load balancing:

• Scaling requirements

• Organizational requirements

• Number of users in a given site

• Requirement for high availability or resiliency

Lync Server 2013 Server Roles that

support load balancing

Enterprise

Edition Front

End Server

Mediation

ServerDirector Server

Edge Server

Guidelines for Deploying DNS Load Balancing for Front End Server Pool

Scenario: Should I deploy DNS Load

balancing on a Front End Server pool?

Is DNS load

balancing

supported?

Is DNS load

balancing

recommended?

Is hardware load

balancer (only)

recommended?

All or most users homed in the pool run Lync Server

2013/2013 clients.Yes Yes

Many users homed in the pool still run older clients. Yes Yes

Interoperates only with other Lync Server 2010/2013

servers.Yes Yes

Interoperates with many servers running Office

Communications Server 2007 R2.Yes Yes

Running Exchange UM with Exchange 2010 SP1 (or not

running Exchange UM)Yes Yes

Running Exchange UM with earlier versions of Exchange

ServerYes Yes

Designing a Coexistence Strategy

• Provide hardware load balancing for all clients and servers

• Retain an existing hardware load balancing setup for legacy clients and legacy servers

• Provide load balancing for Lync 2010/2013 servers and clients only

Hardware

Load Balancing

DNS Load

Balancing

Lync 2010/2013 Server & Clients

Lync Server 2013

Office Communication Server R2 Clients

Module Review and Takeaways

• Review Question(s)

• Real-world Issues and Scenarios

• Tools

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