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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