1. 70-412: Configuring Advanced Windows Server 2012 services
Chapter 1
Configure and Manage High Availability

2. Objective 1.1: Configuring Network Load Balancing

3. Availability
When a server goes down, it most likely causes your company to lose money.
If your network contains an external website or database that controls your sales, ordering, inventory, or production, server downtime can be detrimental to these business needs.
If it is an internal server, it might not allow your users to perform their jobs.
In either case, your company loses money either through lost revenue or lost productivity.
© 2013 John Wiley & Sons, Inc.

4. Fault Tolerance
To make a server more fault tolerant, you should first look at what components are the most likely to fail and implement technology to make a system less likely to fail.
Redundant components could include:
Disks: Use some form of RAID and hot spares.
Power supplies: Use redundant power supplies.
Network cards: Use redundant network cards.
© 2013 John Wiley & Sons, Inc.

5. Network Load Balancing (NLB)
Network Load Balancing (NLB) transparently distributes traffic across multiple servers by using virtual IP addresses and a shared name.
With NLB, you gain fault tolerance and enhanced performance. It is often used with mission-critical web servers but can also be used with other types of servers.
© 2013 John Wiley & Sons, Inc.

6. Heartbeats
NLB can detect the failure of cluster nodes by sending packets known as heartbeats.
NLB cluster heartbeats are transmitted every second between nodes in the cluster.
If a node misses five consecutive heartbeats, the node is automatically removed from the NLB cluster.
© 2013 John Wiley & Sons, Inc.

7. Convergence
When a node is added or removed from a cluster, a process known as convergence occurs, where the cluster determines its current configuration by building a membership of nodes and mapping client requests based on the available nodes.
Convergence can occur only if each node is configured with the same port rules.
© 2013 John Wiley & Sons, Inc.

8. Affinity
Affinity determines how the servers are going to balance the load.
You use affinity settings when you use multiple host filter mode.
© 2013 John Wiley & Sons, Inc.

9. Cluster Operation Mode
On the Cluster Parameters tab, you configure the virtual IP address, subnet mask, and DNS name that the cluster will use.
You also can configure the cluster operation mode, which specifies whether a multicast MAC address should be used for cluster operations.
© 2013 John Wiley & Sons, Inc.

10. Objective 1.2: Configuring Failover Clustering

11. Failover Cluster
A failover cluster is a set of servers that work together to increase the availability of services and applications.
The clustered servers (called nodes) are connected through a network connection (physical or virtual) and by software.
If one of the nodes fails, another node begins to provide services (a process known as failover).
Failover clusters can be used for a wide range of network services including database applications such as Exchange Server or SQL Server, file servers, or network services such as Dynamic Host Control Protocol (DHCP) services.
© 2013 John Wiley & Sons, Inc.

12. Failover Cluster Components
Nodes
Servers that make up the cluster and that run the Cluster service.
They host the associated cluster resources and applications.
In Windows Server 2012, a failover cluster can have 64 physical nodes and can run 4,000 virtual machines on each cluster.
Windows Server 2008 R2 supported only 16 physical nodes and 1,000 virtual machines per cluster.
© 2013 John Wiley & Sons, Inc.

13. Failover Cluster Components
Network: A common network that connects the cluster nodes. Three types of networks can be used in a cluster: public, private, and public-and-private.
Cluster storage: A storage system that is shared between cluster nodes and usually connects using fiber channel or iSCSI.
Clients: Computers (or users) that use the Cluster service.
Cluster service: The service running on Windows servers that manages and coordinates cluster resources to provide high availability.
© 2013 John Wiley & Sons, Inc.

14. Quorum
A quorum is used with a failover cluster to determine the number of failures that the cluster can sustain.
If a quorum (the majority of the votes) is not reached, the cluster will stop running.
Each voting element contains a copy of the cluster configuration, and the Cluster service works to keep all copies synchronized at all times.
© 2013 John Wiley & Sons, Inc.

15. Quorum Configuration Quorum Configuration
Node Majority
Node and Disk Majority
Node and File Share Majority
No Majority (Disk Only)
When using a witness disk, the disk must be at least 512 MB. It must be dedicated for cluster use and not assigned to a clustered role. It cannot be a volume that is a CSV.
© 2013 John Wiley & Sons, Inc.

16. Objective 1.3: Managing Failover Clustering

17. Failover Clustering Roles
Failover clusters provide high availability and scalability to many server applications (e.g., Microsoft Exchange, Microsoft SQL, and Hyper-V).
Use the High Availability Wizard to configure a clustered role (formerly called a clustered service or application), which is a service or application that you make highly available.
© 2013 John Wiley & Sons, Inc.

18. General Use File Server Role
File servers in a cluster can be configured for general use—General Use File Server—which is almost the same as it was in Windows Server 2008 R2.
It provides a central location for users to share files or for server applications that open and close files frequently.
It also supports SMB, Network File System (NFS), Data Deduplication, File Server Resource Manager, DFS Replication, and other File Services role services.
The only significant difference between Windows Server 2008 R2 and Windows Server 2012 is that Windows Server 2012 supports SMB 3.0.
© 2013 John Wiley & Sons, Inc.

19. Scale-Out File Server
The Scale-Out File Server, introduced in Windows Server 2012, can be used with a cluster. It is intended for application data such as Hyper-V VM files and for file shares that require reliability, manageability, and high performance.
Unlike a General Use File Server cluster, the Scale-Out File Server cluster is an active-active failover cluster where all file shares are online on all nodes simultaneously.
Although the Scale-Out File Server supports SMB, it does not support NFS, Data Deduplication, DFS Replication, or File Server Resource Manager.
© 2013 John Wiley & Sons, Inc.

20. Highly Available Virtual Machine
One popular use of failover clusters is with Hyper-V to provide highly available virtual machines (VM).
To make a VM highly available, the VM storage location must be on shared storage that all nodes can access. In addition, the storage needs to be configured as a CSV.
© 2013 John Wiley & Sons, Inc.

21. Objective 1.4: Managing Virtual Machine Movement

22. Understanding Virtual Machine Movement
For a server administrator, virtual machines are one of the best tools to use for providing functionality on demand.
With relative speed and ease, you can deliver additional applications as soon as they are needed rather than waiting for the purchase of new hardware.
© 2013 John Wiley & Sons, Inc.

23. Live Migration
Live migration (LM) allows you to move the entire VM or its storage from one physical host to another without interrupting your users.
This process is sometimes referred to as a “shared nothing” migration because the storage is mirrored over the network to the destination server while the VM continues to run and provide network services.
To perform an LM, follow these four steps:
Configure LM prerequisites.
Configure LM security (constrained delegation , if needed).
Configure the source and destination computers for LM.
Move a running virtual machine or VM storage.
© 2013 John Wiley & Sons, Inc.

24. Move Options The three options to move virtual machines:
Move the VM’s data to a single location: This is simplest.
Move the VM’s data by selecting where to move the items: This provides the most options for where you can store the various components.
Move only the VM: This requires shared storage and allows you to move the VM without moving the virtual hard disk.
© 2013 John Wiley & Sons, Inc.

25. Quick Migration
Windows Server 2012 includes way to move a Live VM that is hosted in a cluster called quick migration (QM).
Quick migration is another process of moving a running VM from one physical host to another. However, QM occurs within the confines of a cluster.
Quick migration allows you to:
Consolidate physical servers
Maintain availability during maintenance
Quickly restore services after service outages
© 2013 John Wiley & Sons, Inc.

26. Storage Migration As VMs grow, they may outgrow their initial storage.
Storage migration is yet another way to move live VM data without disrupting users.
The three options are:
Move the VM’s data to a single location: This is simplest.
Move the VM’s data by selecting where to move the items: This provides the most options for where you can store the various components.
Move only the VM: This requires shared storage and allows you to move the VM without moving the virtual hard disk.
© 2013 John Wiley & Sons, Inc.

27. P2V and V2V
A physical machine to virtual machine (P2V) migration takes an existing physical computer and converts it into a virtual machine.
P2V migration can be performed with either Microsoft System Center 2012 SP1 (SC12) – Virtual Machine Manager (VMM or SCVMM) or the Disk2vhd tool from the Microsoft Sysinternals website.
A virtual machine to virtual machine migration (V2V) converts an existing virtual machine to a different file format. Currently, SCVMM supports migrations from VMware, XenServer, or OVF.
© 2013 John Wiley & Sons, Inc.