Introduction
In the world of technology, Unix systems are often perceived as complex, designed exclusively for a niche group of specialists with advanced knowledge. IBM AIX, one of the most mature and stable Unix systems, is frequently seen as difficult to master. However, in my opinion, the reality is quite different. With the right approach, AIX can be surprisingly accessible, even for individuals just starting their journey in system administration. What most deters people from using it is the fear of the unknown and its niche status compared to more popular systems like Linux.
In this article, we will explore the basics of AIX, demonstrating that understanding its features and mechanisms does not have to be a daunting task. You’ll learn key concepts, discover how to quickly start working effectively with this system, and, most importantly, find out where to begin. Whether you're a beginner or an experienced system administrator, AIX can become a valuable ally in your daily work.
It’s important to note that AIX is an enterprise-class system designed specifically for servers. While Linux distributions often overlap between server and desktop use and share common software repositories, AIX lacks features like sound support, Bluetooth, Wi-Fi, and similar components because they are unnecessary.
AIX is minimalist, free of unnecessary software or any bloatware, as it is designed to operate reliably and ensure the continuity of mission-critical business systems.
Basic information
The AIX (Advanced Interactive eXecutive) system is part of the UNIX family of operating systems, created by IBM, and primarily used in corporate environments. AIX is designed to run exclusively on IBM Power servers and is closely integrated with PowerVM virtualization and the Power processor architecture.
On one hand, AIX is a highly advanced system, but on the other, it includes various enhancements that make daily work with it more enjoyable compared to many other operating systems.
Commands specific to AIX are quite logical. Most display commands start with "ls" (list), commands that modify the system begin with "ch" (change), and commands for removing items start with "rm" (remove).
There are many tasks in AIX that require executing just one command, whereas performing the same action on a Linux distribution often involves multiple steps. This is particularly evident when detecting new devices, working with SAN arrays, and managing file system space. Administrators also have access to the SMIT tool (described later in this article), which enables many administrative tasks even without knowing the exact commands to use in a given situation.
Using ready-made Ansible collections for AIX (available at Ansible Galaxy - https://galaxy.ansible.com/ui/repo/published/ibm/power_aix) significantly improves administration and automation. It is highly recommended to leverage these tools and learn how to use them early in your AIX administration journey, especially if your organization already uses Ansible Automation Platform or AWX for automating other systems.
AIX operates on Power servers and architecture, optimized for this technology. Thanks to this, it supports up to 8 processor threads, which should be considered when analyzing CPU load, especially at the beginning of learning AIX. For example, if 8 CPUs are assigned to the system with SMT-8 (8 threads) enabled, the system will display 64 logical processors. This can be somewhat confusing for novice administrators. AIX allows operation not only with 8 threads but also with 4, 2, or in single-threaded mode, and the SMT (Simultaneous Multithreading) setting can be changed online.
It’s worth noting that AIX is predominantly run within PowerVM virtualization. As a result, it is typically deployed in an LPAR (Logical Partition/Virtual Machine), where resources like CPU and RAM can be dynamically allocated or removed.
AIX versions
Currently, the actively developed versions are AIX 7.2 and AIX 7.3. As of the time of writing, both are supported and maintained by IBM.
One of the key responsibilities of administrators is to ensure that the system is running on a supported version, as IBM’s support services are closely tied to system versioning. Operating an outdated, unsupported version of AIX could lead to IBM declining service requests.
Maintaining supportability for AIX is essential and should not be overlooked. Regardless of how knowledgeable or experienced system administrators may be, there is always a risk of encountering a bug or issue that cannot be resolved without IBM’s assistance, such as a dedicated patch or a configuration change recommendation.
End-of-support dates can be tracked on the following websites:
To check the AIX version, you can use the oslevel -s command. A sample output might look like this:
# oslevel -s
7300-02-02-2420
Here’s what the result means:
- 7300: Indicates the AIX version. In this case, version 7.3.
- 02: The Technology Level (TL), which is 2.
- 02: The Service Pack (SP), which is 2.
- 2420: The build sequence identifier, specifying the year and week of the release, i.e., the 20th week of 2024.
In IBM AIX, the terms Technology Level (TL) and Service Pack (SP) refer to different levels of updates and support for the operating system:
- Technology Level: Major, regularly released updates that introduce new features, performance improvements, security patches, and compatibility enhancements.
- Service Pack: Updates that include bug fixes and security patches for a specific TL.
There are also Interim Fixes (iFix) - temporary fixes released in response to specific issues, provided until they are incorporated into a future TL or SP.
Where to Gain Knowledge?
Beginner administrators often struggle to find reliable sources of information, so I’ve compiled a list of resources that I believe are useful. It’s important to remember that the official IBM documentation should always take precedence.
With so much material available, it’s easy to feel overwhelmed. To start, I recommend Sebastian Biedroń’s book and hands-on learning by working directly with the system.
In case you have access to the AIX system, it is worth using the basic administrative commands described below, as the most effective way to learn is to combine theory with practice.
Learning Through Practice: Working with the System
If you have access to an AIX environment, whether through PowerVS Cloud or you’ve unexpectedly become the lucky administrator of a production system running critical services, it’s highly beneficial to start by familiarizing yourself with basic commands and tools.
What commands can you safely run as a beginner without causing harm? Below is a suggested initial set to help you get started.
- Basic Information about the AIX System
uname -a - Displays the system name, nodename, version, machine ID.df -g - Information about filesystem usage (similar to Linux, but instead of the -h option, use -g for GB or -m for MB). It's worth reviewing the role of visible filesystems by checking their descriptions in the documentation: https://www.ibm.com/docs/en/aix/7.3?topic=tree-file-system-structure).oslevel -s - Displays AIX system version, Technology Level, and installed Service Pack.prtconf - Displays information such as server model, processor generation, and number of assigned CPU and RAM resources.lparstat -i - Displays a name and parameters of LPAR. lssrc -a - Displays the status of all subsystems.
- POSIX commands, e.g.,
ls, cat, grep, cd, pwd - Familiar commands for Linux and Unix administrators and users (https://en.wikipedia.org/wiki/List_of_POSIX_commands).
- System Load Monitoring and Processes
- Disks, LVM, and Filesystems
lspv -u - Lists Physical Volumes with their UID numbers.lsvg - Displays Volume Group informationlslv XXX - Displays information about the logical volume XXX lsfs - Lists filesystems.mount - Displays mounted local and remote filesystems.lsps -a - Lists paging spaces.
- Network Configuration
ifconfig -a - Displays the status of network interfaces and assigned IP addresses.netstat -nr - Displays the routing table.lsattr -El inet0 - Displays attributes of the inet0 device and routing table entries.lsattr -El en0 - Displays attributes of the en0 network interface.
- Devices and Their Parameters
lsdev - Lists devices in the systemlsdev -Cc adapter - Lists adapterslscfg - Displays system configuration and device information (VPD - Vital Product Data)
- Installed Software
lslpp -L - Lists installed Filesets (software packages).emgr -l - Lists installed iFixes
- Event Log
errpt -a - Lists system errors and events.
Administrator Challenges
Working with AIX can vary depending on the scope of responsibilities in your organization. In some companies, there are dedicated teams that manage both system administration and PowerVM virtualization, while in others, these responsibilities may be divided among multiple teams.
- Daily Work (Maintenance and Development)
- Monitoring and analyzing statistics, reacting to events in the system log, performance analysis, parameter tuning, automation creation, maintaining configuration standards, adding resources.
- Working with code, especially in a DevOps culture (Git, Ansible, CI/CD).
- Security management, tracking vulnerabilities.
- Periodic Tasks
- Upgrading AIX versions (Technology Level, Service Pack, installing iFixes), migrating e.g. from AIX 7.2 to 7.3.
- Infrastructure changes (e.g., replacing storage arrays or upgrading servers to newer generations).
- E.g., migrating data to new storage systems via LVM, migrating LPARs between physical servers
- IBM Cases/PMRs
- Reporting problems, providing necessary data for analysis, consultations, installing delivered fixes, and applying recommendations.
What Should an AIX Administrator Be Able to Do?
- Perform system backups and restores.
- Install iFixes, upgrade the system to a higher Technology Level or Service Pack.
- Manage disk space.
- Monitor system health.
- Troubleshoot performance issues.
- Follow security best practices, hardening of the system, and meet security requirements
- Adjust the system for application requirements, such as for Oracle databases.
- Automate repetitive tasks.
It’s important to think about automation and infrastructure-as-code concepts, CI/CD, and working in a DevOps culture early on in your AIX journey.
SMIT Tool
SMIT (System Management Interface Tool) is an interactive tool available from the CLI that allows you to perform many system configuration tasks in AIX. It’s particularly useful for beginner administrators, but advanced users also use it. Using SMIT helps avoid errors such as typos, allows you to perform tasks without knowing the exact commands, and is simply more convenient.
File System Structure
Directories in the file system structure have specific meanings. In the case of AIX, some of them serve as mount points for separate logical volumes, allowing them to be isolated from each other. For example, if the /tmp filesystem gets full, it won't affect the free space in the /usr filesystem.
For more information on the structure, refer to the documentation: https://www.ibm.com/docs/pl/aix/7.2?topic=tree-file-system-structure
/ - The root directory of the system. All other filesystems are mounted as subdirectories of this directory./etc/ - Contains system configuration files./dev - Contains device files, both hardware and virtual devices./usr/ - Stores programs, libraries, and system files./home - Intended for users' home directories./opt - Intended for additional software not part of the operating system./tmp - Used for temporary data./var - Stores variable data such as system logs, temporary files, and print buffers./var/adm/ras - A directory for AIX diagnostic logs.
LVM (Logical Volume Manager)
LVM is the foundation for working with disk space in AIX, and it’s essential to understand it. It provides flexibility, redundancy, and easy storage expansion, allowing for dynamic configuration changes without interrupting system operation. It differs from the LVM implementation found in HP-UX or Linux, though some commands are similar (e.g., pvdisplay = lspv, vgextend = extendvg). It's also important to note that, unlike Linux and Windows systems, AIX doesn't use partitions, which is a significant advantage.
- PV (Physical Volume) - The basic unit in LVM, typically a single disk in AIX without using a traditional partition. PV forms the base for building the LVM layers.
- VG (Volume Group) - A group of volumes that combines PVs into a single logical unit. It’s the foundation for creating LVs.
- LV (Logical Volume) - A logical volume created from the available space in the VG, which can be used to create a filesystem or SWAP.
- PP (Physical Partition) - a smal unit of storage that is used within a Physical Volume. Physical partitions are like "bricks" that make up the PV space. Each logical partition maps to physical partition
- Filesystem - provides space for files (in AIX, typically in JFS or JFS2 format), which can be created on an LV.
For more details, refer to the documentation: https://www.ibm.com/docs/en/aix/7.3?topic=management-logical-volume-manager
Vi Text Editor
Vi is a specific and well-known text editor in Unix-based systems, and it has even spawned various jokes, such as:
"How to generate a random string of characters? Ask a Windows user to exit Vi."
"I've been using Vi for 10 years, mostly because I don't know how to exit."
You can love or hate it, but its definite advantage is that it’s available on almost every Unix system. Therefore, every AIX administrator should know it at least at a basic level - https://www.ibm.com/docs/en/aix/7.2?topic=v-vi-command
Alter Disk Copy and mksysb
AIX offers tools that are hard to find in other operating systems. Some of the most useful ones are mksysb and alt_disk_copy, which allow you to create a copy of the AIX system. It’s a good idea to use them before installing patches or upgrading the operating system version, even during normal system operation.
alt_disk_copy
This tool allows you to clone the AIX system to an alternate disk connected to the same LPAR. Cloning enables an easy return to a previous state in case of problems, as switching to the alternative disk happens via a restart.
Example command to copy the system disk without modifying the bootlist:
alt_disk_copy -B -d hdiskX
mksysb
This tool creates a backup of the AIX operating system. In addition to restoring the AIX system in case of failure, it allows you to create a system image that can be installed on another server. It can also be helpful in migration scenarios, especially when Live Partition Mobility isn't possible. Ensure that the mksysb image file is stored in a location other than the operating system's disk space.
Example command to create a mksysb image:
mksysb -i /backup/image_mksysb
PowerVM Virtualization basics
Not every AIX administrator deals with physical servers and PowerVM virtualization, but it’s useful to know at least the basic concepts to communicate better with the team responsible for virtualization and hardware.
For an introduction to basic PowerVM virtualization concepts, feel free to read my other article: Discover the Power of IBM Power - PowerVM Virtualization
- Processor Virtualization: Entitled Capacity, Virtual/Dedicated Processors, Capped/Uncapped Shared Processors
- LPAR Profiles: Minimum, Desired, Maximum values, physical/virtual adapters, processor compatibility mode.
- VIOS Systems
- HMC Console.
- Disk access: NPIV and vSCSI
- Network virtualization: SEA, SR-IOV.
- Live Partition Mobility.
Conclusion
In this article, I’ve tried to highlight key topics related to AIX system administration. While they might seem complex at first, over time, you will realize that the perceived difficulty of AIX often stems from preconceived notions or a lack of basic knowledge. This powerful operating system offers not only stability and reliability but also intuitive tools that simplify IT infrastructure management. The key is to take a step-by-step approach-gradually exploring the system’s functions and capabilities. The more time you spend practicing, the more you’ll appreciate AIX’s flexibility and versatility. With the right resources and a little patience, AIX can become your favorite operating system, and mastering it will bring significant benefits to your daily administration tasks and career development.
