Shulou(Shulou.com)06/01 Report--

I. introduction to AlwaysOn

AlwaysOn availability groups are a new feature available in SQL Server 2012 to ensure the availability of application data and achieve zero data loss. AlwaysOn availability group technology combines the advantages of database clustering and database mirroring. one of the benefits of this technology is to provide non-shared storage, which can avoid the failure of the whole availability scheme caused by a single point of failure of storage.

AlwaysOn availability groups are based on the database (group) level and delimit a set of user databases (which can be one or more) into a group. Each set of availability databases is hosted by an availability copy. Availability copies include one primary copy and one to four secondary copies. The primary replica is used to host the primary database, and the secondary replica hosts a set of secondary databases and serves as a potential failover target for the availability group. The master copy makes the master database available for the read-write connection of the client, realizing the change operation to the database. Synchronization is also performed at the database level. The primary copy sends the transaction log records for each primary database to each secondary database. Each secondary copy caches transaction log records and then restores them to the corresponding secondary database. The primary database is independently synchronized with the secondary database of each connection. Therefore, a secondary database can hang or fail without affecting other secondary databases, and a primary database can hang or fail without affecting other primary databases.

A Windows Server failover cluster (WSFC) cluster is required to deploy AlwaysOn availability groups. Each availability copy of a given availability group must be on a different node of the same WSFC cluster. When you deploy AlwaysOn availability groups, one WSFC resource group is created for each availability group. The WSFC cluster monitors this resource group to determine the status between nodes in order to evaluate the health of the master replica. Fail-over occurs when a failure occurs, and arbitration for AlwaysOn availability groups is based on all nodes in the WSFC cluster, regardless of whether a given cluster node hosts any availability copies.

Users can provide client connections to the master copy of a given availability group by creating an availability group listener. The availability Group listener connects the resources of a given availability group with a DNS name to direct client connections to the appropriate availability copy.

AlwaysOn availability groups allow you to synchronize a set of databases to up to four read-only replicas, a new feature introduced by SQL Server 2012. SQL Server 2014 increases the number of read-only copies to 8

2. Deployment environment preparation 1. Deployment environment

Computer name

IP address

Operating system

Role

Remarks

DC01.contoso.com

10.0.0.2

Win2012R2

DC, DNS server

Provide arbitration folder

SQL01.contoso.com

10.0.0.3,20.0.0.2

Win2012R2

SQL Server 2014 WSFC cluster node

AlwaysOn availability group name SG01

SQL02.contoso.com

10.0.0.4,20.0.0.3

Win2012R2

SQL Server 2014 WSFC cluster node

SQLCluster

10.0.0.5

Failover cluster name

SQL

10.0.0.10

Listener name

two。 Create a failover cluster

Configure LAN and heartbeat networks for SQL01 and SQL02

Add roles and functionality wizards in SQL01 and SQL02 to select failover clusters

Create a failover cluster name computer SQLCluster

Add cluster nodes SQL01 and SQL0 to the security attribute and give full access

After the creation is completed, disable the account

Open failover Cluster Administrator and create a cluster

Add member server node

Enter the cluster computer account number SQLCluster before you create it.

After the cluster is created successfully, the computer account is automatically enabled and the dns record is created

Create an arbitration witness folder in the domain controller

Configure cluster quorum

III. Install SQL Server

Install a local stand-alone SQL on SQL01 and SQL02

IV. Enable AlwaysOn

Create a new database

The recovery model must be a full model

Back up this database

Enable folder sharing for Backup

Open the New availability Group Wizard

Enter availability group name

Select the databases that need to be added to the availability group

Add a copy and select Node 2 SQL02

Five. create a listener

Enter the name and IP of the listener. Later, we visit SQL and manage the access through this FQDN and IP address.

VI. Test cluster

The current SQL running node is SQL01

Shut down the LAN network card of SQL01 for testing

When the network card is disabled, SQL automatically switches to the SQL02 and becomes the active node

When we visit SQL at this time, we will find that the SQL02 secondary node is now the primary node.

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