Solution Guide for Migrating Oracle on UNIX to SQL Server - Willy .Net

304 Stabilizing PhaseFor example, with respect to applications, there may be a failure when the number ofsimultaneous connections hit 100. This could be because of the limitation of somevariable associated with the code segment related to connection handling. Similarproblems may be encountered only during stress testing because there will bedifferences in resource consumption and low-level implementation of the same functionsbetween the UNIX and Windows plat<strong>for</strong>m.Resolving Stress IssuesStress testing should be per<strong>for</strong>med only after all issues encountered during per<strong>for</strong>mancetesting have been fixed. Bugs encountered during stress testing can be because of theapplication, the hardware configuration, or resource availability. Issues or bugs found withthe application have to be sent to the development team with any pertinent in<strong>for</strong>mation. Ifthe issues relate directly to hardware or hardware resources, they can be solved byconfiguration or adding additional resources.For example, SQL Server is not configured to take advantage of memory more than 2 GBby default. If your hardware contains additional memory, this issue can be resolved bycorrectly configuring SQL Server to take advantage of the server's available memory.Microsoft offers two utilities, Read80Trace and OSTRESS, to assist in stress testingSQL Server. To learn more or download these utilities, refer tohttp://support.microsoft.com/?kbid=887057.For detailed in<strong>for</strong>mation on scalability, refer to the following resources:● Scaling out on SQL Serverhttp://www.microsoft.com/resources/documentation/sql/2000/all/reskit/en-us/part10/c3861.mspx.● SQL Server Scalability FAQhttp://www.microsoft.com/sql/techinfo/administration/2000/scalabilityfaq.asp.● Microsoft SQL Server 2000 Scalability Project — Server Consolidationhttp://msdn.microsoft.com/library/default.asp?url=/library/enus/dnsql2k/html/sql_asphosting.asp.● Windows 2003 Per<strong>for</strong>mance and Scalabilityhttp://www.microsoft.com/windowsserver2003/evaluation/per<strong>for</strong>mance/perfscaling.mspx.Scalability TestingScalability testing is per<strong>for</strong>med to determine if the solution scales to handle an increasingworkload. The workload may be increased size, as in Very Large Databases (VLDB), ormore activity, such as transactions. Activity scalability is measured in number of userconnections, requests, reports, <strong>for</strong> example. The overall scalability is also dependent onthe hardware and the application. The application's throughput change as the load isincreased is a measure of its scalability. Also, the throughput may be measured withincreased resources along with the increased load.Scalability testing, while similar to stress testing, provides additional in<strong>for</strong>mation to assistin future solution expansion plans. Scalability testing is conducted to record how well themigrated solution will scale or increase throughput as the user workload increases. Itdiffers from stress testing because scalability testing will generally load the solution farpast the minimum load levels defined in the Planning Phase.If additional hardware is available, it is worthwhile to determine whether exceeding thelimits of the current solution requires a simple addition of hardware or a completeredesign of the system.