Compaq EK-SMCPO-UG. C01 Environmental

RAID Array Controller 2-21

Compaq Confidential – Need to Know Required

Writer: Bob Young Project: RAID A rray 3000 Pedestal Storage Subsystem Hardware User’s Guide Comments:

Part Number: EK-SMCPO-UG. C01 File Name: c-ch2 RAID Array Controller.doc Last Saved On: 12/4/00 1:51 PM

Initialization

During initialization, the firmware in the RAID 3000 verifies that both

controllers have consistent configurations including identical memory cache

and system parameters. If the controller setups are incompatible, the set is not

bound and each controller operates in stand-alone mode.

Message Passing

Information is shared between the two controllers by a collection of messages

passed through the backplane connectors. The messages provide configuration

data as well as a heartbeat which is transmitted by each controller every

500 ms. If a controller does not receive a heartbeat within one second, it

assumes the peer controller has become inoperable and begins failing over.

If the controllers cannot exchange messages due to communication problems

over the backplane, they will break the connection and each controller will

switch to a stand-alone mode.

Failover

Failover describes the process of transferring data from a failed controller to a

survivor and completing any active tasks. When one controller begins the fail-

over process, it sends a reset to the other controller, which prevents the failing

unit from processing any more information and enables any host ports that are

passive. It then downloads the failed controller’s cache to its unused portion of

cache and begins acting upon that data.

While downloading the data, the controller responds to I/O by disconnecting

(if allowed) and waiting approximately three seconds before reconnecting and

presenting a Busy status. The delay is to prevent host operating systems from

seeing too many errors and fencing off the controller.

Environmental

The controller incorporates a set of on board sensors to detect abnormal

operating conditions that may affect data safety.

Contents

Main Compaq StorageWorks Page Contents About This Guide Chapter 1 Product Overview Chapter 2 RAID Array Controller Chapter 3 Maintenance Chapter 4 Expansion Pedestal Option Chapter 5 Second Controller Option List of Figures Page List of Tables Page About This Guide Purpose and Scope Intended Audience Document Structure Page Related Documents Table 1 Related Documents Text Conventions Symbols in Text Symbols on Equipment xiv RAID Array 3000 Pedestal Storage Subsystem Hardware User's Guide Compaq Confidential Need to Know Required This is a test Rack Stability Getting Help Compaq Technical Support Compaq Website Compaq Authorized Reseller Chapter 1 Product Overview Product Description Page Product Overview 1-3 Table 1-1 RAID Array 3000 Pedestal Part Numbers and Model Descriptions Pedestal Features Pedestal Cabinet Page Pedestal Components StorageWorks Building Blocks (SBBs) RAID Array Controller Pedestal Power Supplies UPS Environmental Monitor Unit (EMU) Product Overview 1-9 Figure 1-5 shows the Pedestal rear panel components. Figure 1-5. Pedestal rear panel components UltraSCSI Buses Product Overview 1-11 Figure 1-8. Slot locations and SCSI ID addresses Figure 1-7. UltraSCSI bus configuration switch Connecting the Pedestal to a Host System Product Overview 1-13 Figure 1-9 shows the Single host, Single Adapter Cabling diagram. Host System Table 1-2 Single Host, Single Adapter Cabling 1-14 RAID Array 3000 Pedestal Storage Subsystem Hardware Users Guide Figure 1-10 shows the Single host, Dual Adapter/dual Controller Cabling diagram. Table 1-3 Single Host, Dual Adapter/Dual Controller Cabling Product Overview 1-15 Table 1-4 Single Host, Single Adapter/Dual Controller (Y-cable connection cabling) 1-16 RAID Array 3000 Pedestal Storage Subsystem Hardware Users Guide Figure 1-12 shows the Dual host, Single Adapter/single Controller Cabling diagram. Table 1-5 Dual Host, Single Adapter/Single Controller Cabling Product Overview 1-17 Specifications Table 1-6 Pedestal Technical Specifications 1-18 RAID Array 3000 Pedestal Storage Subsystem Hardware Users Guide Table 1-7 Pedestal Physical and Power Specification Chapter 2 RAID Array Controller Controller Overview Page Controller Features Page Table 2-1 Controller Specifications Page Controller Reset and LED Indicators Table 2-2 LED/Reset Switch Interface Flexible RAID Set Configuration Performance Enhancements Custom Components Efficient Write and Read Algorithms Write-Back Caching Write Gathering Write On Top RAID Levels Supported Table 2-3 RAID Levels Supported Table 2-4 Pedestal RAID Set Restrictions RAID 0 Page RAID 1 RAID 0+1 Table 2-5 RAID 0+1 Example RAID 4 Page RAID 5 Just a Bunch of Drives (JBOD) Redundant Operation Initialization Message Passing Failover Environmental Backup Power Management Table 2-6 Response to Various AC Power Condition s Voltage Monitoring Temperature Monitoring Page Page Chapter 3 Maintenance Pedestal Status and Power LEDs SBB Status LEDs Table 3-1 Disk Drive SBB Status LEDs Controller LEDs EMU Error Reporting EMU Error Conditions Replacing Components (FRUs) Removing the Pedestal Door Replacing an SBB Page Replacing a Power Supply Replacing the RAID Array Controller Replacing the EMU Board Replacing the UPS Differential/Wide UltraSCSI Bus Table 3-2 SCSI Bus Length and External Cables Table 3-3 Assigned Slot Device Addresses in the Pedest al Reconfiguring the SCSI Bus Page Page Maintenance 3-17 Replacing the Controller Memory Cache Modules Page Page Chapter 4 Expansion Pedestal Opt ion Product Description Expansion Pedestal Cabinet Page Expansion Pedestal Components Page Reconfiguring Base Pedestal UltraSCSI Bus Page Page Page Page Page Page Expansion Pedestal Option 4-15 UPS, and the AC power source (Figure 415). Chapter 5 Second Controller Option Second Controller Option Kit Installing the Upgrade Saving Existing Configuration Updating Firmware Updating Firmware Using SWCC Updating Firmware Using Serial Interface Shutting Down the RA3000 Installing Two SIMMs into Second Controller Replacing Existing Controller Restoring the Configuration Updating Firmware on Second Controller Installing Original Controller Configuring a Dual Controller Installation for a Single Serial Port Configuring the RA3000 for the Active Mode of Operation Configuring the Dual Controllers Connecting to Your Dual Controller Storage System Verifying the Controller Operating Parameters