Intel SRCU42L User Guide - Page 27

Hardware Specifications and Features Table 3-4. Configurable Disk Drive SCSI Parameters Disconnect Enabled / Disabled Automatic Enabling this setting allows for the disk drive to disconnect from the SCSI bus when it's not participating in a transfer. This allows for optimal bus utilization by all devices on the bus. Tagged Queues On / Off Automatic When enabled, this feature allows the SCSI disk drive to execute more than one command at a time. Disk Read and Write Cache On / Off Configurable For performance reasons, the Read Ahead and Write cache of the hard disk drives should always be on. This is the default setting. 3.5.3 Configurable I/O Controller SCSI Parameters When the controller starts up, its SCSI parameters are automatically set to their optimal settings. Manual configuration is not required. However, you can customize I/O SCSI parameters for each channel on the controller by using the Storage Console menu Advanced Setup > Configure Controller > Controller Settings. Table 3-5. Configurable I/O Controller SCSI Parameters Parameter Domain Validation Setting/Value On / Off Description When this is set to On, Domain validation allows for a cyclical check of the correct data transfer at a given rate for the respective channel. 3.6 RAID Controller Drive Limitations (Host, Array, Logical, and Physical) The following are limitations assuming the following: • U320 speed hard disk drives • Dual channel SCSI controller • Cabling that meets U320 specifications Physical drives are limited by the number of SCSI channels being controlled by the RAID controller. The firmware/software supports a maximum of 15 hard disk drives per channel (or 14 if one SCSI ID is being occupied by an intelligent enclosure processor). The maximum number of array drives is limited by the RAID firmware. The actual limit of the SRCU42L controller is 15 array drives per dual-channel controller. A RAID array drive requires a minimum of two hard disk drives (or logical drives). Therefore the maximum RAID array drive limitation for the SRCU42L controller is the physical drive limit divided by two. A RAID array drive can contain (or have reside on it) up to a maximum of 2 host drives. There is a maximum limitation of 30 host drives per SRCU42L controller. There is a minimum of at least one host drive per array drive. A host drive can only be associated with (or reside on) a single array drive. Hardware Installation and User's Guide 27