HP Surestore Disk Array FC60 HP SureStore E Disk Array 12H User's and Service - Page 105

Concepts and Management Optimizing Performance Optimizing Performance Disk array performance is influenced by many factors, some host-related, some related to the configuration of the disk array itself. Host-related disk array performance issues can typically be identified and corrected using operating system utilities or third-party applications designed for this purpose. The following list identifies some of the factors that directly influence disk array performance. Other factors, such as a rebuild, can temporarily affect array performance. • Amount of available RAID 0/1 - In most cases, the more RAID 0/1 space available, the better the disk array performance. With enough RAID 0/1 space, the disk array can service all write I/Os from RAID 0/1, thus allowing an optimum write working set. RAID 0/1 space can be increased by increasing the amount of unallocated capacity on the disk array. • Enabling Active Hot Spare - With Active Hot Spare enabled, the disk array can recover quickly from a disk failure without the need for any action on your part. This maintains performance because while the disk array is operating in non-redundant or critical mode, performance decreases. Active Hot Spare provides an additional performance benefit because it is used as RAID 0/1 space until a disk fails. • Amount of cache DRAM - Increasing the amount of cache DRAM can alleviate bottlenecks that may form in the controller data path. This increases the rate at which the disk array can service host I/Os. • Proper disk module installation - Installing the disk modules in the correct slots in the enclosure distributes the disks across the internal SCSI busses and balances the I/O load properly. Disk modules should be installed from left-to-right, top-to-bottom. • Keep the disk capacity small - Having twelve disks with smaller capacities will improve the performance as compared to having twelve disks with larger capacities. 105 Concepts