Dynamically Configuring Devices (Tasks)
This chapter provides instructions for dynamically configuring devices in the Solaris environment. You can add, remove, or replace devices in the Solaris environment while the system is still running, if the system components support hot-plugging. If the system components do not support hot-plugging, you can reboot the system to reconfigure the devices.
For information on the procedures associated with dynamically configuring devices, see the following:
For information on hot-plugging USB devices with the cfgadm command, see "Hot-Plugging USB Devices With the cfgadm Command".
For information about accessing devices, see Chapter 29, Accessing Devices (Overview).
Dynamic Reconfiguration and Hot-Plugging
Hot-plugging is the ability to physically add, remove, or replace system components while the system is running. Dynamic reconfiguration refers to the ability to hot-plug system components. This term also refers to the general ability to move system resources (both hardware and software) around in the system or to disable them in some way without physically removing them from the system.
You can hot-plug the following devices with the cfgadm command:
USB devices on SPARC and IA platforms
SCSI devices on SPARC and IA platforms
PCI devices on IA platforms
Features of the cfgadm command include the following:
Displaying system component status
Testing system components
Changing component configurations
Displaying configuration help messages
The benefit of using the cfgadm command to reconfigure systems components is that you can add, remove, or replace components while the system is running. An added benefit is that the cfgadm command guides you through the steps needed to add, remove, or replace system components.
For step-by-step instructions on hot-plugging SCSI components, see cfgadm(1M) and "SCSI Hot-Plugging With the cfgadm Command". For step-by-step instructions on hot-plugging PCI adapter cards on IA based systems, see "IA: PCI Hot-Plugging With the cfgadm Command".
Note - Not all SCSI and PCI controllers support hot-plugging with the cfgadm command. For a list of PCI hardware that supports hot-plugging, please refer to the Solaris 9 (Intel Platform Edition) Hardware Compatibility List.
As part of Sun's high availability strategy, dynamic reconfiguration is expected to be used in conjunction with additional layered products, such as alternate pathing or fail-over software. Both products provide fault tolerance in the event of a device failure.
Without any high availability software, you can replace a failed device by manually stopping the appropriate applications, unmounting noncritical file systems, and then proceeding with the add or remove operations.
Note - For information about hot-plugging devices on your specific hardware configuration, such as enterprise-level systems, please refer to your hardware configuration documentation.
Attachment Points
The cfgadm command displays information about attachment points, which are locations in the system where dynamic reconfiguration operations can occur.
An attachment point consists of the following:
An occupant, which represents a hardware component that can be configured into the system
A receptacle, which is the location that accepts the occupant
Attachment points are represented by logical and physical attachment point IDs (Ap_Ids). The physical Ap_Id is the physical pathname of the attachment point. The logical Ap_Id is a user-friendly alternative for the physical Ap_Id. For more information on Ap_Ids, refer to cfgadm(1M).
The logical Ap_Id for a SCSI Host Bus Adapter (HBA), or SCSI controller, is usually represented by the controller number, such as c0.
In cases where no controller number has been assigned to a SCSI HBA, then an internally-generated unique identifier is provided. An example of a unique identifier for a SCSI controller is the following:
fas1:scsi
The logical Ap_Id for a SCSI device usually looks like this:
HBA-logical-apid::device-identifier
In the following example, c0 is the logical Ap_Id for the SCSI HBA:
c0::dsk/c0t3d0
The device identifier is typically derived from the logical device name for the device in the /dev directory. For example, a tape device with logical device name, /dev/rmt/1, has the following logical Ap_Id:
c0::rmt/1
If a logical Ap_Id of a SCSI device cannot be derived from the logical name in the /dev directory, then an internally-generated unique identifier is provided. An example of an identifier for the /dev/rmt/1 tape device is the following:
c0::st4
For more information on SCSI Ap_Ids, refer to cfgadm_scsi(1M).
The cfgadm command represents all resources and dynamic reconfiguration operations in terms of a common set of states (such as configured, unconfigured) and operations (connect, configure, unconfigure, and so on). For more information on these common states and operations, see cfgadm(1M).
The receptacle and occupant states for the SCSI HBA attachment points are as follows:
Receptacle State | Description | Occupant State | Description |
|---|---|---|---|
empty | N/A for SCSI HBA | configured | One or more devices configured on the bus |
disconnected | Bus quiesced | unconfigured | No devices configured |
connected | Bus active |
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Receptacle and occupant states for SCSI device attachment points are as follows:
Receptacle State | Description | Occupant State | Description |
|---|---|---|---|
empty | N/A for SCSI devices | configured | Device is configured |
disconnected | Bus quiesced | unconfigured | Device is not configured |
connected | Bus active |
|
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The state of SCSI attachment points is unknown unless there is special hardware to indicate otherwise. For instructions on displaying SCSI component information, see "How to Display Information About SCSI Devices".