S1000-007 IBM AIX v7 Administrator Specialty Questions and Answers

Devices that are connected to the system can be in one of four states.

Devices that are connected to the system can be in one of the following states:

Item

Description

Undefined

The device is unknown to the system.

Defined

Specific information about the device is recorded in the customized database, but it is unavailable to the system.

Available

A defined device is coupled to the operating system, or the defined device is configured.

Stopped

The device is unavailable but remains known by its device driver.

If a tty device and a printer alternately use the same tty connector, both a tty device and a printer are defined on the same parent and port in the device configuration database. Only one of these devices can be configured at a time. When the tty connector is configured, the printer specific setup information is retained until it is configured again. The device is not removed; it is in the defined state. Maintaining a device in defined state retains customized information for a device that is not currently in use, either before it is first made available or while it is temporarily removed from the system.

If a device driver exists for a device, the device can be made available through the device driver.

https://www.ibm.com/docs/en/aix/7.2?topic=nodes-device-states

The command used to monitor SAN I/O performance/throughput is iostat -DIRT 60 10. The iostat command is used to monitor I/O performance and throughput on a SAN device. The DIRT (Disk I/O Response Time) flag can be used to display the response time for each I/O request. The last two arguments, 60 and 10, are the interval (in seconds) and the number of iterations respectively. This command will monitor I/O performance/throughput every 60 seconds for 10 iterations.

When a customer calls with a complaint about slow workload performance, it is important to ask for additional details to help pinpoint the source of the issue. This could include details such as which application or process is running slowly, what errors are appearing, how long the issue has been occurring, etc. Having this information will help the administrator to determine the cause of the problem and determine the best course of action. Reference: IBM AIX v7 Administrator Specialty Study Guide (page 5-29).