PERC 4/Di FeaturesDell™ PowerEdge™ Expandable RAID Controller 4/Di User's Guide
The Dell™ PowerEdge™ Expandable RAID controller (PERC) 4/Di is a chip on the motherboard that offers RAID control capabilities. PERC 4/Di supports all single-ended and low-voltage differential (LVD) SCSI devices on Ultra3 and Wide SCSI channels with data transfer rates up to 320 MB/s (Megabytes per second).
PERC 4/Di provides reliability, high performance, and fault-tolerant disk subsystem management. It is an ideal RAID solution for the internal storage of Dell's workgroup, departmental, and enterprise systems. This RAID controller offers a cost-effective way to implement RAID in a server and provides reliability, high performance, and fault-tolerant disk subsystem management.
The PERC 4/Di features include:
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NOTE: This includes boot support for "legacy disks". This means there is boot support for the operating system installed on the drive attached to the legacy SCSI channel. This function is required in the embedded configuration utility. |
Table 1-1 shows the maximum length of cable that you can use for 320M SCSI, either single-ended or low voltage differential (LVD).
| Standard |
Single-Ended |
LVD |
Maximum Number of Devices |
|---|---|---|---|
Ultra320 SCSI |
N/A |
12M (39' 4") | 15 |
PERC 4/Di supports the following operating systems:
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NOTE: See the Dell PERC 4/Di Operating System Driver Installation Guide for driver installation procedures for the operating systems. |
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NOTE: The maximum number of drives you can use depends on your system configuration. |
The RAID controller works with cache memory and a card key to provide two SCSI channels to support configurations on a backplane. Configurations can span PERC 4/Di internal disks, and external enclosure disks.
You can select SCSI or RAID mode in the system setup. Use this option for a RAID channel for hard drives, and a legacy SCSI channel for removable devices or pre-existing hard drives. Devices attached to the SCSI channel are not controlled by the RAID firmware and appear to work as if they are attached to a regular SCSI controller.
This is the case if the platform for your system supports it. Not all PERC 4/Di systems support RAID/SCSI mode.
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NOTICE: You will lose data if the configuration is changed from SCSI to RAID or RAID to SCSI. |
Table 1-2 displays the possible combinations of SCSI and RAID modes for Channels 0 and 1.
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NOTE: SCSI/SCSI is not a RAID configuration and is available only if you disable the RAID software by selecting SCSI mode in the system BIOS. (Access the system BIOS by pressing <F2> during bootup). See the PERC 4/Di Operating System Driver Installation Guide to learn how to select SCSI and RAID modes in the system BIOS. |
Table 1-2. SCSI and RAID Modes
| Mode |
Channel 0 |
Channel 1 |
|---|---|---|
RAID |
RAID |
RAID |
RAID/SCSI (if supported by your platform) |
RAID |
SCSI |
SCSI |
SCSI |
SCSI |
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NOTE: You cannot set Channel 0 as SCSI, while Channel 1 is set as RAID. |
During bootup, you can press <F2> to access system setup to set SCSI or RAID as the mode for the two channels, Channel 0 and Channel 1. You can set Channel 0 in RAID mode and Channel 1 to SCSI mode (known as RAID/SCSI mode), or set both to RAID mode or both to SCSI mode.
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NOTE: Refer to the PERC 4/Di Operating System Driver Installation Guide for details and procedures for each operating system. |
In RAID mode, the channel supports RAID capabilities; in SCSI mode, the channel operates as a SCSI channel. If both channels are in SCSI mode and you want to change one channel to RAID, it is recommended that you leave the SCSI channel that contains the operating system in SCSI mode.
Please read all restrictions and disclaimers.