1.4. Step 4: Determine High Availability, Security and Isolation Strategies Determining your high availability and security requirements are very important as they can influence the type of Hyper-V hardware you purchase and dictate where you place your SQL Server virtual machines. 1.4.1. High Availability Strategies By choosing the appropriate high availability options, it is possible to meet your business continuity service level agreements, enable data protection and improve manageability of your SQL Server virtualized environment. Here are details of each high availability strategy: 1.4.1.1. High Availability with Live Migration A common SQL Server high availability strategy employed by many organizations is Live Migration. With Live Migration, running SQL Server virtual machines can be moved from one Hyper-V physical host to another Hyper-V physical host without service disruption or downtime. This is displayed in figure 4. As mentioned earlier, Live migration is integrated with Windows Server 2008 R2 Hyper-V and Microsoft Hyper-V Server 2008 R2 and requires the failover clustering feature to be added and configured on the servers running Hyper-V. By leveraging Live Migration, architects and database administrators can continue to ensure service continuity and maintain their SQL Server virtualization high availability objectives even during planned maintenance. Figure 4. Achieving High Availability with Live Migration 1.4.1.2. High Availability with Guest Clustering Using iSCSI Another SQL Server high availability option involves guest clustering using iSCSI. Guest failover clustering, as illustrated in Figure 5 makes the provisioning of clusters possible in a virtual environment. A guest failover cluster is simply SQL Server failover clusters inside virtual machines with nodes operating as virtual machines. SQL Server 2005, SQL Server 2008 and SQL Server 2008 R2 support guest failover clustering. The shared storage required to build a cluster is connected to each virtual machine by means of iSCSI. SQL Server guest cluster nodes can all run on the same physical host machine or on different physical host machines. If SQL Server guest clustering is running on the same host, business operations and high-availability will be compromised if the host becomes unavailable. Therefore, consider running the active node and standby node of a SQL Server guest cluster on different physical host machines to maintain high availability and reduce interruptions in business operations with your SQL Server virtual machines. Figure 5. Achieving High Availability with Guest Clustering
1.4. Step 4: Determine High Availability, Security and Isolation Strategies Determining your high availability and security requirements are very important as they can influence the type of Hyper-V hardware you purchase and dictate where you place your SQL Server virtual machines. 1.4.1. High Availability Strategies By choosing the appropriate high availability options, it is possible to meet your business continuity service level agreements, enable data protection and improve manageability of your SQL Server virtualized environment. Here are details of each high availability strategy: 1.4.1.1. High Availability with Live Migration A common SQL Server high availability strategy employed by many organizations is Live Migration. With Live Migration, running SQL Server virtual machines can be moved from one Hyper-V physical host to another Hyper-V physical host without service disruption or downtime. This is displayed in figure 4. As mentioned earlier, Live migration is integrated with Windows Server 2008 R2 Hyper-V and Microsoft Hyper-V Server 2008 R2 and requires the failover clustering feature to be added and configured on the servers running Hyper-V. By leveraging Live Migration, architects and database administrators can continue to ensure service continuity and maintain their SQL Server virtualization high availability objectives even during planned maintenance. Figure 4. Achieving High Availability with Live Migration 1.4.1.2. High Availability with Guest Clustering Using iSCSI Another SQL Server high availability option involves guest clustering using iSCSI. Guest failover clustering, as illustrated in Figure 5 makes the provisioning of clusters possible in a virtual environment. A guest failover cluster is simply SQL Server failover clusters inside virtual machines with nodes operating as virtual machines. SQL Server 2005, SQL Server 2008 and SQL Server 2008 R2 support guest failover clustering. The shared storage required to build a cluster is connected to each virtual machine by means of iSCSI. SQL Server guest cluster nodes can all run on the same physical host machine or on different physical host machines. If SQL Server guest clustering is running on the same host, business operations and high-availability will be compromised if the host becomes unavailable. Therefore, consider running the active node and standby node of a SQL Server guest cluster on different physical host machines to maintain high availability and reduce interruptions in business operations with your SQL Server virtual machines. Figure 5. Achieving High Availability with Guest Clustering
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