Dell PowerVault 35F User Manual

Also see for PowerVault 35F: Manual User guide Manual Installation guide

Dell PowerVault 35F User Manual Manual pdf 20 page image

Understanding the PowerVault 35F Configuration: Dell PowerVault 35F User's Guidefile:///C|/Users/rishi_sood/Desktop/35F/ug/config_1.htm[3/21/2013 11:16:19 AM]is at least one address available on the loop that is connected to the PowerVault 35F. Fibre Channel supports up to 126devices on an arbitrated loop.Hard AddressingWhen acquiring a hard address, the PowerVault 35F attempts to acquire the AL_PA value that was specified by userconfiguration. If the desired address is not available at loop initialization time, the PowerVault 35F comes up on theloop in non-participating mode. This allows the loop to continue to operate, although the unit will not be accessible viathe Fibre Channel interface. This would occur when another device on the arbitrated loop has acquired the sameaddress as that configured on the PowerVault 35F.Hard addressing is recommended for environments where it is important that the device addresses do not change.Device address changes can affect the mapping represented by the host operating system to the application, and haveadverse effects. An example of such an environment would be a tape library installation, where the applicationconfiguration requires fixed device identification for proper operation. Hard addressing will insure that the deviceidentification to the application will remain constant.When connected to a Fibre Channel Switch, the PowerVault 35F is identified to the switch as a unique device by thefactory programmed World Wide Name (WWN). No further configuration is needed, although the WWN can beconfigured to a user-defined value through the configuration interface.General SCSI ConfigurationThe PowerVault 35F appears on each SCSI bus as a single initiator. The default initiator ID is 7, and can be set viaconfiguration to any valid SCSI address. No other devices on the SCSI bus may use this address.The PowerVault 35F provides the capability to reset the SCSI buses during the boot cycle. This allows the devices on aSCSI bus to be in a known state. Configuration allows this feature to be enabled or disabled. This feature is enabled inthe default configuration. Configurations using multiple devices that have long reset cycles, or are adversely affectedby bus resets, should disable this feature.The PowerVault 35F negotiates for the maximum values for transfer rates and data width on a SCSI bus. If an attacheddevice does not allow the full rates, the unit will use the rates negotiated for that device. Negotiation is on a devicespecific basis, so the unit can support a mix of device types on the same bus.Fibre Channel Host to SCSI Target ConfigurationThis section describes the configuration of the PowerVault 35F when acting as a target to a Fibre Channel Initiator,passing Fibre Channel Protocal (FCP) requests through to SCSI target devices.This is configured as the default, using soft addressing on the Fibre Channel loop and auto addressing for the targetdevice mapping. Auto addressing is described further in this section.The PowerVault 35F automatically detects if it is connected to an FL or F_Port, and will use the appropriate typewithout further configuration.Address MappingThe PowerVault 35F supports three addressing methods for mapping SCSI targets to Fibre Channel Hosts: