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System Overview

Dell™ PowerVault™ 220S and 221S Systems Service Manual

	Overview		Components and Indicators
	System Features		Technical Specifications
	Service Features

Overview

Dell™ PowerVault™ 220S and 221S systems are reliable, flexible, external SCSI expansion enclosures designed to support multiple Dell storage environments and RAID configurations. Each system offers maximized drive-spindle count, hot-plug hard drives, optional redundant power supplies, redundant cooling modules, rackmount capability, systems management features, and a modular design for easy upgrades. Most major components, including hard drives and power supply/cooling modules are hot-pluggable and can be removed and replaced easily. The enclosure management module (EMM), split-bus module, and SCSI terminator card are "warm-pluggable." This means they can be removed or inserted while the power is on, but all I/O activity has ceased.

This section provides an overview of system features and components, and technical specifications.

System Features

Your system offers the following features:

• Tower or rack versions (3 units [U] [19 inches]).
  
  
• Capacity for fourteen 1-inch hot-plug SCSI hard drives. (See "Technical Specifications" or your system's readme file for supported hard-drive speeds and capacities.)
  
  
• Universal hard-drive carriers.
  
  
• Support for a variety of RAID controller cards, host-integrated RAID controllers, and host bus adapter (HBA) cards. (See your system's readme file for supported RAID controllers and HBA cards.)
  
  
• Hot-plug power supply and cooling modules that are combined for easy serviceability. The cooling modules are redundant. Power supply modules can be redundant or nonredundant.
  
  
• Optional redundant enclosure management modules (EMM).
  
  
• Support for the following direct-attach configurations:
  
  
• High-availability redundant EMM configuration in joined-bus mode (with a terminator card for nonredundant configurations).
  
  
• High-availability cluster configurations (with redundant EMMs) that allow multiple-server access to the same enclosure.
  
  
• Split-bus module (with redundant EMMs) to operate the enclosure using two separate buses.
  
  
• Enclosure management through in-band SCSI enclosure services (SES) for power supplies and cooling modules and SCSI-accessed fault-tolerant enclosures (SAFTE).
  
  
• Storage management through Dell OpenManage™ Array Manager.
  
  
• Four sensors for monitoring ambient temperatures and shutdown capability when temperatures reach a critical level.
  
  
• Audible warning for critical component failure.
  
  
• Supported for all new Dell servers. (See your system's readme file for supported systems.)

Service Features

Your storage system was designed for easy serviceability. All hard drives, power supplies, cooling modules, EMMs/SCSI terminator cards, and split-bus modules can be removed and replaced without having to remove system covers or other components.

Components and Indicators

Front-Panel Components and Indicators

Figure 1 shows the front-view orientation of both systems.

Figure 1. System Orientation

1 PowerVault 220S 2 PowerVault 221S

Figure 2 illustrates LED indicators and components on the system's front panel. Table 1 lists conditions indicated by each LED.

Figure 2. Front-Panel Features

1 busy LED indicator 2 status LED indicator 3 hard drives (14) 4 over-temperature LED indicator 5 split-bus LED indicator 6 cluster LED indicator 7 shelf-fault LED indicator 8 power LED indicator

Table 1. Front Panel Indicators

LED Indicator	LED Icon	Condition
Power (green)		At least one power supply is supplying power to the system.
Shelf-fault (amber)		One of the following conditions has occurred: power-supply failure, EMM failure, cooling-module failure, over-temperature condition, split-bus module not installed, or firmware currently being downloaded. For more information, see "Basic Troubleshooting."
Cluster (green)		The system is configured for cluster mode. For more information, see "Split-Bus Module."
Split-bus (green)		The system is configured for split-bus mode. For more information, see "Split-Bus Module."
Over-temperature (amber)		An over-temperature condition has occurred (the system will shut down when the temperature inside the box exceeds 50°C [122°F]). For more information, see "Basic Troubleshooting."

Hard-Drive Carrier LED Indicators

Each of your system's 14 hard-drive carriers has two LED indicators: a busy indicator and a status indicator (see Figure 2 for location). Table 2 shows the hard-drive LED indicators with the associated LED icons. Table 3 lists the flash patterns for the hard-drive status indicator.

Table 2. Hard-Drive Carrier LED Indicators

LED Indicator	LED Icon	Condition
Busy (green)		The hard drive is active on the SCSI bus. NOTE: This LED is controlled by the hard drive.
Status (green and amber)		See Table 3 for flash patterns and conditions.

Table 3. Hard-Drive Carrier Status Indicator Flash Patterns

Back-Panel Features and Indicators

Figure 3 illustrates the back-panel features for systems with redundant EMMs and redundant power supplies. Figure 4 illustrates the back-panel features for nonredundant systems. See Figure 5, Figure 6, and Figure 8 for more detail on the back-panel indicators.

Figure 3. Back-Panel Features (Systems With Redundant EMMs and Redundant Power Supplies)

1 unused port 2 cooling module 3 power supply 4 power supply 5 cooling module 6 unused port 7 EMM 8 split-bus module 9 EMM

Figure 4. Back-Panel Features (Systems With Nonredundant EMMs and Nonredundant Power Supplies)

1 SCSI terminator card 2 cooling module 3 power-supply blank 4 power supply 5 cooling module 6 unused port 7 EMM 8 split-bus module

Back-Panel Modules

Figure 5 illustrates the features and indicators on the back-panel modules. See Figure 6 for more information about bus configuration switch modes.

Figure 5. Back-Panel Modules Features and Indicators

1 bus configuration switch 2 power LED indicator 3 SCSI connector 4 active LED indicator 5 fault LED indicator 6 power LED indicator

Split-Bus Module

Your system supports three SCSI bus modes controlled by the split-bus module:

• Joined-bus mode
  
  
• Split-bus mode
  
  
• Cluster mode

These modes are controlled by the position of the bus configuration switch when the system is turned on. Figure 6 illustrates the switch position for each mode. For more information on configuring the SCSI bus modes, see your Installation and Troubleshooting Guide.

Figure 6. Bus Configuration Switch Modes

1 joined-bus mode (switch position is up for rack systems, right for tower systems) 2 split-bus mode (switch position is center both for rack and tower systems) 3 cluster mode (switch position is down for rack systems, left for tower systems)

The only difference between cluster mode and joined-bus mode is the SCSI ID assigned to the enclosure services processor on the EMM. When cluster mode is detected, the processor SCSI ID changes from 6 to 15. As a result, SCSI ID 15 is disabled, leaving 13 available hard drives in cluster mode. This allows a second initiator, such as a host bus adapter or RAID controller card on a second host server, to use SCSI ID 6 (see Table 4 for SCSI ID assignments and Figure 7 for associated hard drives).

Table 4. SCSI ID Assignments

Figure 7. SCSI ID Numbers and Associated Hard Drives

See Table 5 for a description of split-bus module modes and functions.

NOTE: To change the SCSI bus mode, you must change the position of the bus configuration switch before turning on the storage system. Changing the position of the bus configuration switch while the system is on will not affect system operation. If you change the configuration, you must first reboot the storage system and then the host server for the changes to take effect. For more information on SCSI bus modes, see your Installation and Troubleshooting Guide.

Table 5. Split-Bus Module Modes

Mode	LED Icon	Position of Bus Configuration Switch	Function
Joined-bus mode		Up for rack systems, right for tower systems	LVD termination on the split-bus module is disabled, electrically joining the two SCSI buses to form one contiguous bus. In this mode, neither the split-bus nor the cluster LED indicators on the front of the system (see Figure 2 for locations) are illuminated.
Split-bus mode		Center for all systems	LVD termination on the split-bus module is enabled and the two buses are electrically isolated, resulting in two seven-drive SCSI buses. The split-bus LED indicator on the front of the system (see Figure 2 for location) is illuminated while the system is in split-bus mode.
Cluster mode		Down for rack systems, left for tower systems	LVD termination is disabled and the buses are electrically joined. The cluster LED on the front of the system (see Figure 2 for location) is illuminated while the system is in cluster mode.

The split-bus module has only one LED indicator (see Figure 5 for LED location), which is illuminated when the module is receiving power.

Enclosure Management Module (EMM)

The EMM serves two primary functions in your storage system:

• SCSI bus expansion — Acts as a buffer for the SCSI bus, electrically dividing the bus into two independent segments while logically allowing all SCSI bus traffic to pass through it transparently. The buffer improves the quality of the SCSI signals and allows longer cable connections.
  
  
• Management functions — Includes SES and SAFTE reporting to the host server, control of all system LED indicators, and monitoring of all environmental elements, such as temperature sensors, cooling modules, and power supplies.

A system with redundant enclosure management features has two EMMs that are designated as primary and secondary that can be configured in either a cluster or joined-bus mode. A system with nonredundant enclosure management has one EMM and one SCSI terminator card configured in a joined-bus mode or two EMMs configured in a split-bus mode. In redundant EMM systems, only one EMM per SCSI bus is active at one time, so only one EMM per SCSI bus can respond to SCSI commands from an initiator.

In joined-bus and cluster modes, if a secondary EMM receives a message that the primary EMM has failed, the fault LED indicator on the primary EMM is illuminated and the condition is reported back to the host server. The secondary EMM will then become active and hold the failed primary in a state of reset until it is replaced. If the primary EMM detects that the secondary has failed, the secondary's fault LED indicator is illuminated and the failed status is reported back to the host server.

NOTE: In split-bus mode, although each EMM monitors the entire storage system, it controls only half of the hard-drive slots. If one EMM fails in split-bus mode, the second EMM will report the failure, but will not assume control of the hard-drive slots that were previously controlled by the failed EMM.

NOTE: The EMM is "warm-pluggable." This means it can be removed or inserted while the power is on. However, all I/O activity between the host and the storage system must be stopped.

The primary EMM is always plugged into the slot on the left (viewed from the back of the system). In systems with redundant EMMs configured for joined-bus mode, the primary EMM assumes control of all the system's functionality. In addition, the active EMM is the only module that reports status of the system to the host server through SES and SAFTE protocols. Because the secondary EMM must assume the responsibilities of the primary in the event that the primary fails, both the primary and secondary EMMs are continuously monitoring the status of the system's components.

Table 6 lists the conditions for each EMM LED indicator. See Figure 5 for location of the LED indicators.

Table 6. EMM LED Indicators

LED Indicator	LED Icon	Condition
Power (green)		The system is receiving power.
Fault (amber)		An EMM has failed.
Active (green)		The EMM is operating normally and performing all the responsibilities of the primary EMM.

Power Supply/Cooling Modules

Your system supports two combined power supply and cooling modules. While the system is designed to operate normally with only one functional power supply, both cooling modules (each with two blowers) must be present for proper cooling. If only one power supply is needed, a blank must be inserted into the other slot to mount the second cooling module. In this nonredundant power-supply configuration, the power-supply blank has the capacity to transfer power and control signals to and from the cooling module.

When a power supply fails, fan speeds increase to provide additional cooling. In addition, when replacing power supplies, fan speeds also increase until the replacement power supply or power supply blank has been installed.

NOTICE: The maximum amount of time that power supply and cooling modules may be removed from the system while it is operating is 5 minutes. If power supply and cooling modules are not replaced within 5 minutes, the system begins to overheat. When the system reaches a critical temperature, it shuts down to prevent damage to the system.

The cooling module is securely mounted to the power supply using a hook-and-latch fastener. This simplifies the removal and installation of cooling modules and power supplies.

Figure 8 illustrates the power supply and cooling module features and LED indicators. Table 7 lists the function of each power supply and cooling module indicator.

Figure 8. Power Supply and Cooling Module LED Features and Indicators

1 blower A fault LED indicator 2 blower B fault LED indicator 3 on/off switch 4 AC connector 5 AC status LED indicator 6 fault LED indicator 7 power-on LED indicator

Table 7. Power Supply and Cooling Module LED Indicators

Module Icon	LED Indicator	LED Icon	Function
Power supply	Power on (green)		DC output voltages are within specifications.
	Fault (amber)		One of the DC output voltages is not within specifications.
	AC status (green)		AC input voltage is within specifications regardless of the position of the power switch.
Cooling module	Blower A fault (amber)		Cooling module blower A has failed.
	Blower B fault (amber)		Cooling module blower B has failed.

Audible Alarm

The primary EMM activates an audible alarm if any of the shelf-fault conditions listed in Table 1 occur. If a critical event occurs, the alarm sounds continuously. If a noncritical event occurs, the alarm sounds every 10 seconds. Table 8 lists critical and noncritical events.

NOTE: The audible alarm is disabled by default. To enable the alarm, you must change the default setting using your array management software. For more information, see your array management software documentation.

NOTE: When the system is on and a split-bus module is not detected, the audible alarm will sound regardless of whether it is enabled or disabled.

Table 8. Audible Alarm Critical and Noncritical Events

NOTE: It is rare for both EMMs to fail simultaneously. However, if this event occurs, the system cannot issue critical or noncritical event alarms for any system component. If both power supplies fail simultaneously, the system can issue critical or noncritical event alarms only if 5-V power is available.

Technical Specifications

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