HP Surestore Disk Array FC60 HP SureStore E Disk Array FC60 Service Manual (A5 - Page 74

• Global hot spares - although none of the configurations use global hot spares, their use is recommended to achieve maximum protection against disk failure. For more information, see "Global Hot Spare Disks" on page 59. • Split bus operation - With three or fewer disk enclosures, increased performance can be achieved by operating the disk enclosures in split bus mode, which increases the number of SCSI busses available for data transfer. However, operating the disk enclosures in split bus mode may make if more difficult to expand the capacity of the array. In a split bus configuration, it may be necessary to take down the host, back up data, and recreate volume groups when adding disk enclosures. If you anticipate the need to expand your disk array, you may want to consider selecting a configuration that uses more enclosures operating in full bus mode. In addition to simplifying expansion, this type of configuration also gives you greater flexibility when creating volume groups. • Segment size - the recommended segment size is 16 Kbyte for RAID 5, and 64 Kbyte for RAID 1 and RAID 0/1. • Maximum volume groups - A maximum of 30 volume groups can be configured on the disk array. One Disk Enclosure Configuration Note A single disk enclosure configuration is not recommended for environments where high availability is critical. For optimum high availability, at least two disk enclosures are required. This protect against the failure of a single disk enclosure. • Hardware Configuration - Two disk array controllers connected directly to host Fibre Channel adapters - One disk enclosure with ten 73 GBytes disk modules - Disk enclosure configured for split-bus mode (two SCSI channels) • Volume Group Configuration - Five RAID 1 volume groups, each comprising two disks (1+1) - Each disk in a volume group is on a separate SCSI channel 74 Recommended Disk Array Configurations