D2L Assignment Week 14 – High Availability Flashcards Preview

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Flashcards in D2L Assignment Week 14 – High Availability Deck (24)
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1
Q
  1. What advantages does deploying Network Load Balancing provide to an organization?
A

NLB eliminates a single point of failure if only one server is configured. It also allows for spreading the network load over multiple servers to prevent overloading one server.

2
Q
  1. What is the group of servers that work together to provide NLB called?
A

They are called an NLB Cluster.

3
Q
  1. Describe the network addressing associated with a NLB Cluster.
A

Each cluster member is assigned a unique IP address. The cluster itself is assigned a single shared IP address which is used by clients to make requests.

4
Q
  1. How do servers within the cluster communicate with each other?
A

Servers use a Heartbeat signal every second to maintain consistent cluster membership.

5
Q
  1. Describe the two modes used for distributing incoming requests between the different servers within the cluster.
A

You can configure Unicast mode where the MAC addresses used by cluster hosts are replaced by a single cluster MAC address. Cluster hosts require a second NIC to communicate with each other.

You can configure Multicast mode where a common multicast MAC address is used by cluster hosts. Cluster hosts are able to communicate with each other so additional NICs are not available.

6
Q
  1. What prerequisites need to be met before creating a NLB Cluster?
A

You must install the necessary services such as IIS for web traffic and be running the same version and edition of Windows Server. You must configure static IP addresses on each server. Optionally, you can install a second NIC to allow communication between individual servers in the cluster.

7
Q
  1. Summarize the tasks to follow when creating an NLB Cluster.
A
  • Configure cluster DNS records. Host record for the cluster.
  • Install the NLB feature
  • Synchronize the content. Duplicate the content between all cluster members.
  • Configure the Cluster Members. Define the cluster and add each member.
  • Use the NLB Manager console to add/remove members and configure port rules
8
Q
  1. What are ‘Port Rules’ with respect to configuring an NLB Cluster?
A

Port Rules are used to identify the cluster IP address and traffic characteristics such as port number, protocol, and how the traffic is handled by the cluster.

9
Q
  1. Describe the characteristics of Failover Clustering.
A

Failover Clustering is a server feature that increases server availability and fault tolerance. This type of clustering uses shared storage resources unlike NLB and migrates services on failed servers to available servers in the cluster.

10
Q
  1. What methods are available for a cluster to determine whether or not the cluster can continue to run or stop due to member failure?
A

Failover Clustering uses the concept of a quorum to identify when the cluster can continue to run and when it must stop due to a failure in one(or more) of its members.

Methods for determining whether to continue or stop running include:

Node Majority (if more than half of the servers are still running – usually when there is an odd number of servers in the cluster),

Node and Disk Majority (uses a witness disk to keep a copy of cluster configuration information – if a majority of servers is available in addition to the witness disk then the cluster keeps operating),

Node and File Share Majority (the witness disk is stored on a share instead of one of the cluster servers), Cloud Witness (uses the cloud for storing the witness information),

No Majority (as long as one server and the witness disk is running), and Dynamic Quorum (the cluster is dynamically managed using vote assignments based on the state of each node.

11
Q
  1. What are some other important Failover Clustering features?
A

Other important features include: Scale-Out File Server Support, Cluster-Aware Updating, Virtual Machine Monitoring and Management, CSV Enhancements, Guest Clustering, and Active Directory-Detached Cluster support.

12
Q
  1. What hardware and software prerequisites are necessary before implementing failover clustering?
A

Hardware

  • should be certified for Windows Server
  • must pass the Validate a Configuration wizard
  • cluster hosts should have the same NIC, drivers, and storage adapters
  • for redundancy use multiple NIC and storage adapters
  • use SAS SCSI, Fibre Channel, or iSCSI storage controllers

Software

  • use the same OS version, edition, and architecture
  • all nodes should have the same updates and patches installed
  • all nodes should use the same network setting options (DHCP or Static)
  • cluster nodes must be members of the same Active Directory domain.
13
Q
  1. Describe the six steps to follow when deploying a Failover Cluster.
A
  • Configure the shared storage – usually a SAN or SAS SCSI deployment
  • Add the Failover Clustering feature to all cluster members
  • Validate the Cluster Configuration – use the verification wizard
  • Create the Failover Cluster
  • Configure the Quorum
  • Configure the Cluster storage
14
Q
  1. What three network types are available for a cluster?
A

Cluster storage – if implementing a SAN this should only be used for the shared storage.

Cluster Node Communication – use a separate network for the cluster node heartbeat signals.

Client Connections – this network is used by clients to connect to clustered resources and services.

15
Q
  1. Describe the concept of a Multi-Site Cluster.
A

A multi-site cluster is a geographically-dispersed cluster that contain nodes in multiple sites. They are typically connected using WAN links.

16
Q
  1. What maintenance task can trigger a failover within Failover Clustering?
A

Automatic updates can trigger a failover. You can configure Cluster-Aware updating (CAU) to avoid triggering a failover.

17
Q
  1. What are some of the services that Cluster-aware applications are designed to support?
A
DFS Namespace Server
DHCP Server
File Server
Hyper-V Replica Broker
Internet Storage Name Service (iSNS) server
Network File System
Virtual Machines
WINS Server
18
Q
  1. Describe the concept of Hyper-V Replica.
A

Hyper-V Replica allows Hyper-V virtual machines to be replicated from one Hyper-V server to another, which provides fault tolerance.

19
Q
  1. Summarize the prerequisites for deploying Hyper-V Replica.
A

Physical Location - can be in the same physical location or geographically dispersed.

Network – must have sufficient network BW to allow for replication traffic.

Storage HW – shared storage or cluster technologies are not required but each server must have sufficient storage for the VM to be replicated.

Server – must both be running the same version of Windows server.

Domain Membership – replication is easier if both machines are in the same domain but not required.

Encryption – replicated data can be encrypted using certificate-based authentication.

20
Q
  1. What are the four tasks you should complete to implement Hyper-V Replica?
A

Create the virtual machines.

Configure the Replica Server to Accept Replication

Enable Virtual Machine Replication

Monitor the Replication

21
Q
  1. Describe the Storage Replica feature available with Windows Server 2016.
A

Storage Replica allows you to configure block-level replication between either Windows servers or Windows clusters for disaster recovery. It can also be used to stretch a failover cluster across multiple sites to ensure high availiability.

22
Q
  1. What are the two Storage Replica types available?
A

Storage Replica types include

Synchronous Replication where applications running on a Windows server can immediately write data to servers at two or more physical locations at the same time and then acknowledge the disk write operations before being marked as complete by the local server.

With Asynchronous Replication the write operations can occur at the same time, but the acknowledgement between the local hard disk and the replication partner may occur later. This can have better performance, but the risk of lost data if the network fails before the data is replicated properly.

23
Q
  1. What two Storage Replica implementation scenarios can be deployed?
A

Stand-alone configuration where two Windows servers are used as replication partners

Stretch Cluster where storage replication occurs between sites.

24
Q
  1. Describe the concept of Storage Spaces Direct (SSD).
A

SSD allows a single storage pool to function as shared storage within a Windows cluster.

This allows direct-attached storage to create the storage pool which are relatively inexpensive.