Dell EqualLogic PS6210XS EqualLogic Group Manager Administrator s Guide PS Ser - Page 333

• Are users getting the response time they expect? If not, identify which area might be causing the problem: - Operating system problem, as it interacts with storage - Network problem - Application being run or accessed - Storage environment • Use the 80/20 rule. By focusing on 20 percent of the most likely causes of a performance issue, you will solve 80 percent of the problems. • Keep the host perspective in mind when managing the arrays. In particular: - Make sure time is synchronized on all monitoring areas (host, array). - Never assume the cause of a problem. Other issues might be causing skewed data. General best practices for solving performance problems include: • Fix hardware problems immediately, even if the array that is down is the redundant array. Replace failed disks or failed control modules. • Always validate the data you are analyzing to ensure it is accurate. For example, you might need to inspect the physical array to see if it is powered on or check if your switches are connected properly to handle MPIO. • Consider the size of your installation when analyzing your storage data. For example, an enterprise-level installation with a large volume of users and data will experience a greater impact from a small degradation of IOPS than a small company with few users. • When setting up email notification, determine what types of information are most useful. Streamline the information you receive as much as possible. If email notifications are set too broadly, an actual problem might be obscured by too much information. • When using SAN Headquarters to monitor your groups, remember that the historical data collected degrades over time. Use more current data for your analysis. • Look at event and audit logs for other issues. Common Hardware Issues Identifying hardware performance issues can eliminate additional effort elsewhere. Hardware failures can also be a source of performance problems. In addition, the combination of hardware and firmware can affect performance, as can various disk types with different performance characteristics. The basic steps for solving any IT problem also apply to the SAN. Table 62. Hardware Issues Affecting SAN Performance lists some common problems that you should watch for and correct immediately. Table 62. Hardware Issues Affecting SAN Performance Damaged Hardware Typical Symptom Detected By Server NIC Malformed packets Monitor errors at switch Possible Corrective Actions Update NIC drivers Replace NIC Bad cable Wrong class of cables Visible damage Malformed packets Visual inspection Monitor errors at switch Replace cable Defective switch Spontaneous restarts Random lockup Monitor switch with appropriate network Update switch firmware Replace switch Defective array hardware Alerts Monitor PS Series group Monitor SAN Headquarters Contact Dell customer support to replace malfunctioning component About Monitoring 333