SQL Server Version SQL Server 2008 SQL Server 2008 SP1/CU1 SP1/CU1 Subscription Type Pull Pull Delivery Type SQL SQL Transaction Type 1 Transaction / 1 1 Transaction / 1 Command Command Total Commands 347,737 347,737 Delivery Total Work Time 215.68 123.28 74.95% (minutes) Total Tran/Sec 0 0 Total Cmds/Sec 26.87 47.01 Table 6 As can be seen from tests, the use of a WAN Accelerator in a replication topology that communicates via slow WAN speeds can greatly improve performance. From a WAN perspective, SQL replication is very similar to storage replication. As a result, WAN acceleration provides similar benefits. For example, by implementing data reduction, compression, latency mitigation and loss correction, WAN acceleration results in faster replication times, better WAN bandwidth utilization, and faster host server performance - all across wider geographic distances. Effect of Subscription Streams The -SubscriptionStreams parameter can greatly improve aggregate replication throughput. It allows multiple connections to a Subscriber to apply batches of changes in parallel, while maintaining many of the transactional characteristics present when using a single thread. If one of the connections fails to execute or commit, all connections will abort the current batch, and the agent will use a single stream to retry the failed batches. Before this retry phase completes, there can be temporary transactional inconsistencies at the Subscriber. After the failed batches are successfully committed, the Subscriber is brought back to a state of transactional consistency. Figure 10 Test Results No Streams (A) Streams (B) Performance Improvement Server Asia Secondary Site Asia Secondary Site Server 1 Server 1 Operating System Windows Server 2008 Windows Server 2008
SQL Server Version SQL Server 2008 SP1/CU1 SQL Server 2008 SP1/CU1 Subscription Type Pull Pull Delivery Type SQL SQL Transaction Type 1 Transaction / 1 Command 1 Transaction / 1 Command Total Commands 347,737 347,737 Delivery Total Work Time (minutes) 215.68 123.28 74.95% Total Tran/Sec 0 0 Total Cmds/Sec 26.87 47.01 Table 6 As can be seen from tests, the use of a WAN Accelerator in a replication topology that communicates via slow WAN speeds can greatly improve performance. From a WAN perspective, SQL replication is very similar to storage replication. As a result, WAN acceleration provides similar benefits. For example, by implementing data reduction, compression, latency mitigation and loss correction, WAN acceleration results in faster replication times, better WAN bandwidth utilization, and faster host server performance - all across wider geographic distances. Effect of Subscription Streams The -SubscriptionStreams parameter can greatly improve aggregate replication throughput. It allows multiple connections to a Subscriber to apply batches of changes in parallel, while maintaining many of the transactional characteristics present when using a single thread. If one of the connections fails to execute or commit, all connections will abort the current batch, and the agent will use a single stream to retry the failed batches. Before this retry phase completes, there can be temporary transactional inconsistencies at the Subscriber. After the failed batches are successfully committed, the Subscriber is brought back to a state of transactional consistency. Figure 10 Test Results No Streams (A) Streams (B) Performance Improvement Server Asia Secondary Site Server 1 Asia Secondary Site Server 1 Operating System Windows Server 2008 Windows Server 2008
Replication_HADR_CaseStudy.docx