This section describes the features of the RAID controller, such as the configuration features, array performance features, hardware specifications, RAID management utilities, and operating system software drivers.
Compatibility with Arrays Created on Existing RAID Controllers
The RAID controller recognizes and uses drive arrays created on existing RAID controllers without risking data loss, corruption, redundancy or configuration loss. Similarly, the arrays created on the PERC 4/Di/Si and 4e/Di/Si controllers can be transferred to other PERC 4/Di/Si and 4e/Di/Si controllers.
NOTE: If you have questions about compatibility, contact your Dell Support Representative.
SMART Technology
The self-monitoring analysis and reporting technology (SMART) detects predictable drive failures. SMART monitors the internal performance of all motors, heads, and drive electronics.
Patrol Read
Patrol Read involves the review of your system for possible hard drive errors that could lead to drive failure, then action to correct the errors. The goal is to protect data integrity by detecting physical drive failure before the failure can damage data. Patrol Read adjusts the amount of RAID controller resources dedicated to Patrol Read operations based on outstanding disk I/O.
Patrol Read starts only when the controller is idle for a defined period of time and no other background tasks are active, though it can continue to run during heavy I/O processes.
You can use the BIOS Configuration Utility to select the Patrol Read options, which you can use to set automatic or manual operation, or disable Patrol Read. See Patrol Read in RAID Configuration and Management for detailed information about Patrol Read.
NOTE: Pause/Resume is not a valid operation when Patrol Read is set to Manual mode.
Background Initialization
Background initialization is the automatic check for media errors on physical drives It makes sure that striped data segments are the same on all physical drives in an array.
NOTE: If you cancel background initialization, it automatically re-starts within 5 minutes. You cannot
permanently cancel the background initialization.
The background initialization rate is controlled by the rebuild rate set using your array management software. The default and recommended rate is 30%. You must stop the background initialization before you change the rebuild rate or the rate change will not affect the background initialization rate. After you stop background initialization and change the rebuild rate, the rate change takes effect when you restart background initialization.
NOTE: Unlike initialization of logical drives, background initialization does not clear data from the drives.
LED Operation
The LED on the drive carrier indicates the state of each drive. For internal storage enclosures, see the storage enclosure user's guide for more information about the blink patterns.
PassThru (Legacy) SCSI Channel
The RAID controller provides the ability to use a passthru (legacy) SCSI channel. This is known as "RAID/SCSI mode." Use this option for one RAID channel for hard drives and a legacy SCSI channel for removable devices or pre-existing hard drives. You can select this option in system setup interface. This is available for PERC 4/Di and 4e/Di only.
Devices attached to the SCSI channel are not controlled by the RAID firmware and function as if they are attached to a regular SCSI controller.
NOTE: The passthru SCSI channel is available only on certain platforms. See your system user's guide
for more information.
The devices and capabilities supported under the SCSI channel are:
Hard drives
CD drives
Tape drive units
Tape drive libraries
Support of domain validation, data CRC, double clocking, and packetization
RAID Configuration Information
Table 3-1 lists the configuration features for the RAID controller.
Table 3-1. Features for RAID Configuration
Specification
PERC 4/Di/Si
PERC 4e/Di/Si
Number of logical drives and arrays supported
Up to 40 logical drives and 32 arrays per controller
Up to 40 logical drives and 32 arrays per controller
Support for hard drives with capacities of more than eight gigabytes (GB)
Yes
Yes
Online RAID level migration
Yes
Yes
Drive roaming
Yes
Yes
No reboot necessary after capacity expansion
Yes
Yes
User-specified rebuild rate
Yes
Yes
RAID Performance Features
Table 3-2 displays the array performance features for the RAID controller.
Table 3-2. Array Performance Features
Specification
Description
Maximum number of scatter/gather elements
64
Drive data transfer rate
Up to 320 MB/sec
Maximum size of I/O requests
6.4 MB in 64 KB stripes
Maximum outstanding I/O requests per drive
Limited only to drive capabilities
Stripe sizes
2 KB, 4 KB, 8 KB, 16 KB, 32 KB, 64 KB, or 128 KB
Maximum number of concurrent commands
255 (Linux® supports only 126 concurrent commands. The 255 command limit is in the firmware and the driver limit is lower.)
RAID Management Utilities
Software utilities enable you to manage and configure the RAID system, create and manage multiple disk arrays, control and monitor multiple RAID servers, provide error statistics logging, and provide online maintenance. The utilities include:
BIOS Configuration Utility
Dell OpenManage™ Array Manager for Windows and Netware
Dell OpenManage Storage Management
BIOS Configuration Utility
The BIOS Configuration Utility configures and maintains RAID arrays, clears hard drives, and manages the RAID system. It is independent of any operating system. See RAID Configuration and Management for additional information.
Dell OpenManage Array Manager
Dell OpenManage Array Manager is used to configure and manage a storage system that is connected to a server. Array Manager runs under Novell NetWare, Windows 2000, and Windows Server 2003. Refer to the online documentation that accompanies Array Manager or the documentation section at support.dell.com for more information.
NOTE: You can run the OpenManage Array Manager remotely to access NetWare, but not locally.
Dell OpenManage Storage Management
Storage Management provides enhanced features for configuring a system's locally-attached RAID and non-RAID disk storage. Storage Management enables you to perform controller and enclosure functions for all supported RAID and non-RAID controllers and enclosures from a single graphical or command-line interface without requiring use of the controller BIOS utilities. The graphical interface is wizard-driven with features for novice and advanced users and detailed online help. The command-line interface is fully-featured and scriptable.
Using Storage Management, you can protect your data by configuring data-redundancy, assigning hot spares, or rebuilding failed drives. You can also perform data-destructive tasks. All users of Storage Management should be familiar with their storage environment and storage management.
Supported Operating Systems and Drivers
Drivers are provided to support each PERC 4e/Di/Si RAID controller for the operating systems listed in Table 3-3. See Driver Installation for installation procedures for the drivers.
Table 3-3. Supported Operating Systems
Operating System
PERC 4/Di
PERC 4e/Di
PERC 4e/Si
W2K Server SP4
Y
Y
Y
W2K Advanced Server SP4
Y
Y
Y
WS 2003 Standard Server
Y
Y
Y
WS 2003 Web Server
Y
Y
Y
2003 Small Business Server (SBS)
Y
Y
Y
WS 2003 Enterprise Server
Y
Y
Y
W2K3 EM64T
N
Y
Y
RHEL v2.1 Update 3
Y
Y
Y
RHEL v3.0 Update 2 (EM64T)
N
Y
Y
RHEL v3.0 GOLD
Y
Y
Y
RHEL v3.0 Update 3 (32bit and EM64T)
N
Y
Y
RHEL 4.0 32-bit
Y
Y
Y
RHEL 4.0 EM64T
N
Y
Y
NetWare 5.1 SP8
Y
Y
Y
NetWare 6.5 SP3
Y
Y
Y
Firmware Upgrade
NOTICE: Do not flash the RAID controller firmware while performing a background initialization or data
consistency check as this can cause the procedure to fail.
You can download the latest firmware from the Dell website and flash it to the firmware on the board. The Dell website offers a firmware flash that can be executed from a DOS environment or one that can be launched from within the Microsoft Windows or Linux operating system. To upgrade the firmware on the RAID controller perform the following instructions:
Download the latest RAID controller firmware from the Dell website located at:
http://support.dell.com.
NOTE: If you system does not have a floppy disk drive, download the firmware update utility for
Microsoft Windows or Linux. For systems running Novell Netware that do not have a floppy drive;
create the firmware update diskette on another system, then copy the contents of the floppy to a
bootable USB key or CD-ROM.
Use the unique instructions for each firmware update version that are posted on the Dell
website to complete the firmware update process.
NOTE: A reboot is required after the firmware update is complete.
Fault Tolerance Features
Table 3-4 lists the features that provide fault tolerance to prevent data loss in case of a failed drive.
Table 3-4. Fault Tolerance Features
Specification
Feature
Support for SMART
Yes
Support for Patrol Read
Yes
Drive failure detection
Automatic
Drive rebuild using hot spares
Automatic
Parity generation and checking
Yes
Battery backup for NVRAM to protect configuration data
Yes
Hot-swap manual replacement of a disk unit without bringing the system down
Yes
Hot Swapping
Hot swapping is the manual substitution of a replacement unit in a disk subsystem for a defective one, where the substitution can be performed while the subsystem is running (performing its normal functions). The backplane and enclosure must support hot swap in order for the functionality to work.
NOTE: A backplane or enclosure must support hot swapping in order for the RAID controller to support
hot swapping.
Failed Drive Detection
The firmware automatically detects and rebuilds failed drives. This can be done transparently with hot spares.
RAID Controller Specifications
Table 3-5 lists the RAID controller specifications.
Table 3-5. RAID Controller Specifications
Parameter
PERC 4/Di/Si
PERC 4e/Di/Si
Processor
Intel® i303 64-bit RISC processor @ 100 MHz
Intel® IOP332 I/O processor with Intel XScale Technology
Bus type
PCI Rev. 2.2
PCI Express Rev. 1.0a
PCI Express controller
Intel i303
Intel i303
Bus data transfer rate
Up to 532 MB/sec at 64/66 MHz
Up to 4 GB/sec
Cache memory size
128 MB
256 MB (DDR2)
Cache function
Write-back, Write-through, Adaptive read-ahead, Non read-ahead, Read-ahead
Write-back, Write-through, Adaptive read-ahead, Non read-ahead, Read-ahead
Flashable firmware
1 MB x 8 flash ROM
4 MB × 16 flash ROM
Nonvolatile random access memory (NVRAM)
32 KB × 8 for storing RAID configuration
32 KB × 8 for storing RAID configuration
SCSI data transfer rate
Up to 320 MB/sec per channel
Up to 320 MB/sec per channel
SCSI bus
LVD or single-ended
LVD
SCSI termination
Active
Active
Termination disable
Automatic through cable and device detection
Automatic through cable and device detection
Devices per SCSI channel
Up to 15 wide or seven narrow SCSI devices
Up to 15 wide or seven narrow SCSI devices
SCSI device types
Synchronous or asynchronous
Synchronous or asynchronous
RAID levels supported
0, 1, 5, 10, and 50
0, 1, 5, 10, and 50
Multiple logical drives/arrays per controller
Up to 40 logical drives per controller
Up to 40 logical drives per controller
Online capacity expansion
Yes
Yes
Dedicated and pool hot spare
Yes
Yes
Hot swap devices supported
Yes
Yes
Non-disk devices supported
NOTE: PERC 4/Di/Si and
4e/Di/Si do not support any non-
disk devices except backplanes.
Yes
Yes
Mixed capacity hard drives
Yes
Yes
SCSI Bus
The RAID adapter controls hard drives using Ultra320 SCSI buses (channels) over which the system transfers data in Ultra320 SCSI mode. The PERC 4/Si and 4e/Si controllers control one SCSI channel, while the PERC 4/Di and 4e/Di controls two. The SCSI channel supports up to 15 wide or seven non-wide SCSI devices at speeds up to 320 MB/sec.
SCSI Termination
The RAID controller uses active termination on the SCSI bus conforming to SCSI-3 and SCSI SPI-4 specifications. Termination enable/disable is automatic through cable detection.
SCSI Firmware
The RAID controller firmware handles all RAID and SCSI command processing and supports the features described in Table 3-6.
Table 3-6. SCSI Firmware
Feature
Description
Disconnect/reconnect
Optimizes SCSI bus utilization
Tagged command queuing
Multiple tags to improve random access
Scatter/gather
Single command can transfer data to and from different memory locations
Multi-threading
Up to 189 simultaneous commands with elevator sorting and concatenation of requests per SCSI channel
Stripe size
Variable for all logical drives: 2 KB, 4 KB, 8 KB, 16 KB, 32 KB, 64 KB, or 128 KB. The default is 64 KB.
NOTE: Using a 2 KB or 4 KB stripe size is not recommended due to
performance implications. Use 2 KB or 4 KB only when required by the applications
used. The default stripe size is 64 KB. Do not install an operating system on a logical
drive with less than a 16 KB stripe size.
Rebuild
Multiple rebuilds and consistency checks with user-definable priority.
Firmware Upgrade
You can download the latest firmware from the Dell web site and flash it to the firmware on the controller. Perform the following steps to upgrade the firmware:
Download the latest firmware and driver to a system that has a diskette drive.
The downloaded file is an executable that copies the firmware to a diskette.
NOTE: If your system does not have a floppy disk drive, use the online flash available for Windows,
NetWare, and Linux, or download the file to your hard drive and burn it to CD, then use the CD-ROM.
Place the diskette in the system containing the RAID controller, restart the system and boot
from the diskette.
Run pflash to flash the firmware.
NOTICE: Do not flash the firmware while performing a background initialization or data consistency
check, as it can cause the procedure to fail.
Dell also provides packages for firmware update from an operating system level. Go to support.dell.com for more support.
NOTE: A reboot is required after the firmware update.
RAID Management
RAID management is provided by software utilities that manage and configure the RAID system and the RAID controller, create and manage multiple disk arrays, control and monitor multiple RAID servers, provide error statistics logging, and provide online maintenance. Storage management software is included with your system. They include the following:
BIOS Configuration Utility
Dell Server Assistant®
Dell OpenManage Array Manager for Windows and Novell NetWare
