vsphere-esxi-vcenter-server-55-storage-guide

Chapter 9 Best Practices for Fibre Channel StorageTuning statically balanced storage arrays is a matter of monitoring the specific performance statistics(such as I/O operations per second, blocks per second, and response time) and distributing the LUNworkload to spread the workload across all the SPs.NOTE Dynamic load balancing is not currently supported with ESXi.Server Performance with Fibre ChannelYou must consider several factors to ensure optimal server performance.Each server application must have access to its designated storage with the following conditions:• High I/O rate (number of I/O operations per second)• High throughput (megabytes per second)• Minimal latency (response times)Because each application has different requirements, you can meet these goals by choosing an appropriateRAID group on the storage array. To achieve performance goals:• Place each LUN on a RAID group that provides the necessary performance levels. Pay attention to theactivities and resource utilization of other LUNS in the assigned RAID group. A high-performanceRAID group that has too many applications doing I/O to it might not meet performance goals requiredby an application running on the ESXi host.• Make sure that each server has a sufficient number of HBAs to allow maximum throughput for all theapplications hosted on the server for the peak period. I/O spread across multiple HBAs provide higherthroughput and less latency for each application.• To provide redundancy in the event of HBA failure, make sure the server is connected to a dualredundant fabric.• When allocating LUNs or RAID groups for ESXi systems, multiple operating systems use and share thatresource. As a result, the performance required from each LUN in the storage subsystem can be muchhigher if you are working with ESXi systems than if you are using physical machines. For example, ifyou expect to run four I/O intensive applications, allocate four times the performance capacity for theESXi LUNs.• When using multiple ESXi systems in conjunction with vCenter Server, the performance needed fromthe storage subsystem increases correspondingly.• The number of outstanding I/Os needed by applications running on an ESXi system should match thenumber of I/Os the HBA and storage array can handle.Fibre Channel SAN Configuration ChecklistThis topic provides a checklist of special setup requirements for different storage arrays and ESXi hosts.Table 9‐1. Multipathing Setup RequirementsComponentAll storage arraysTopologyIBM TotalStorage DS 4000(formerly FastT)CommentsWrite cache must be disabled if not battery backed.No single failure should cause both HBA and SP failover, especially with active-passivestorage arrays.Host type must be LNXCL or VMware in later versions.AVT (Auto Volume Transfer) is disabled in this host mode.VMware, Inc. 67