Compaq EK-SMCPO-UG. C01 manual Redundant Operation, Just a Bunch of Drives Jbod

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2-20RAID Array 3000 Pedestal Storage Subsystem Hardware User’s Guide

While RAID 5 is ideally suited for applications with many, small I/O operations, there is no reason why it cannot function equally well for applications with large, sequential I/O operations. This makes RAID 5 an excellent all-purpose RAID level.

CAUTION: RAID 5 can withstand a single failure and handle I/O activity without interruption in degraded mode until the failed drive is rebuilt. If a second drive fails while the RAID set is in degraded mode, the entire RAID set will fail.

Just a Bunch of Drives (JBOD)

JBOD makes it possible to connect one or standalone disk drives to the controller. A JBOD disk drive is not part of a redundancy group, even though the controller assigns a redundancy group number to the drive. This number becomes that logical unit number (LUN) that the host will use to address the drive.

One use for JBOD is to connect a system disk drive to the controller. The drive does not become part of a RAID set, but it is made available to the host on the same SCSI bus as the other devices controlled by the controller.

Redundant Operation

When operating in a redundant configuration, the two controllers are linked such that, in case of a failure, the surviving controller can access the other controller’s cache memory and complete all operations that were in progress when the failure occurred. The controllers support two different configurations:

■Active/Active: One host port is active on each controller. The other port on each controller is passive and only used if the peer controller fails.

■Active/Passive: Both host ports on one controller are active. The other controller’s ports are both passive and only used if the primary controller fails.

When one controller fails, the survivor will process all I/O requests until the failed controller is repaired and powered on. The subsystem will then return to its previous state (that is Active/Active or Active/Passive).

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Contents Compaq StorageWorks Page Contents RAID Array Controller List of Figures RAID 0 write List of Tables Page About This Guide Maintenance Related Documents Text Conventions Symbols in Text This is a test Rack Stability Compaq Website Product Overview Product DescriptionRAID Array 3000 pedestal enclosure drives optional Compaq Part No RA3000 pedestal subsystem with one controller, 230Pedestal Features Pedestal CabinetPedestal front panel major components Pedestal Components StorageWorks Building Blocks SBBsRAID Array Controller Pedestal Power Supplies UPSEnvironmental Monitor Unit EMU EMU circuit board locationShows the Pedestal rear panel components UltraSCSI bus port and default Scsi ID assignments UltraSCSI BusesUltraSCSI bus configuration switch Connecting the Pedestal to a Host System Single Host, Single Adapter Cabling ItemÂDescriptionSingle Host, Dual Adapter/Dual Controller Cabling DescriptionHost System Dual Host, Single Adapter/Single Controller Cabling Specifications Pedestal Technical SpecificationsDimension Pedestal Physical and Power SpecificationPhysical Specifications Power SpecificationsRAID Array Controller Controller OverviewPage Controller Features Bridging the gap between the host and the pedestalUnits created from storagesets, partitions, and disk drives Controller Specifications SpecificationsController Specifications Environmental Controller Reset and LED IndicatorsLED/Reset Switch Interface NameFlexible RAID Set Configuration Shows the front panel of the controllerPerformance Enhancements Custom ComponentsEfficient Write and Read Algorithms Write-Back CachingWrite Gathering Write On TopPedestal RAID Set Restrictions RAID Levels SupportedRAID Levels Supported Max. No. * of DrivesRAID Shows a diagram of a RAID 0 write Diagram of a RAID 1 write RAID 0+1RAID 0+1 Example Drives SelectedFunction Diagram of a RAID 4 write Page Diagram of a RAID 5 write Redundant Operation Just a Bunch of Drives JbodMessage Passing EnvironmentalInitialization FailoverCondition Backup Power ManagementResponse to Various AC Power Conditions ResponseAcceptable System Voltage Levels Voltage MonitoringSystem Voltage Termination VoltageAcceptable External Temperature Levels Temperature MonitoringExternal Temperature Supply VoltageBoard Temperature Acceptable Board Temperature LevelsPage Maintenance Pedestal Status and Power LEDs SBB Status LEDs Shows the Pedestal status LEDsActivity LED Fault LED Indication Controller LEDsDisk Drive SBB Status LEDs EMU Error Reporting EMU Error ConditionsReplacing Components FRUs Removing the Pedestal Door Replacing an SBBReplacing an SBB Replacing a Power Supply Replacing a power supplyReplacing the RAID Array Controller Removing the controller from the pedestalReplacing the EMU Board Tools requiredRemove standoffs from UPS and external fault connectors Differential/Wide UltraSCSI Bus Replacing the UPSAssigned Slot Device Addresses in the Pedestal Reconfiguring the Scsi BusScsi Bus Length and External Cables Rate Bus LengthMaintenance Shows how to remove the screw and panel Close the side panels and replace the cover screw Replacing the Controller Memory Cache Modules 11. Remove controller12 shows how to release the locking clips 14. Install replacement Simm Expansion Pedestal Option Expansion Pedestal Cabinet Shows the Expansion PedestalExpansion Pedestal Option Shows the rear panel power supplies Expansion Pedestal ComponentsEMU Reconfiguring Base Pedestal UltraSCSI Bus Remove the side cover from the base pedestal Figure Disconnect Scsi cable Connect Scsi jumper Remove connector knockout plate 10. Connect Scsi cable Set the bus configuration switch to 7 Figures 4-11 13. Reconfigured Scsi bus addresses 14. Connect Scsi cable between pedestals 15. Power cable connections 16. Transfer drives from base to expansion pedestal Second Controller Option Second Controller Option Kit Second controller pedestal slot locationInstalling the Upgrade Saving Existing ConfigurationUpdating Firmware Using Swcc Updating FirmwareUpdating Firmware Using Serial Interface Firmware update dialog boxShutting Down the RA3000 Installing Two SIMMs into Second Controller Insert Simm into connectorReplacing Existing Controller Remove controller from top slotRestoring the Configuration Restoring configuration to new controller10. Restored configuration example Updating Firmware on Second ControllerInstalling Original Controller Configuring the RA3000 for the Active Mode Operation Configuring the Dual Controllers Connecting to Your Dual Controller Storage System Verifying the Controller Operating Parameters