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To restore AIX on an IBM p690 or p595 server you boot the logical partition from its mksysb system backup, enter the SMS firmware menu to pick the backup device, and run an Install from a System Backup in maintenance mode. This guide walks the full mksysb backup-and-restore workflow end to end, fixes the rough spots in older runbooks, and notes the modern equivalents so the procedure still maps cleanly onto current POWER hardware and supported AIX releases.

Restore AIX recovery is one of the most important skills an AIX system administrator can own. A mksysb image is a bootable, self-contained snapshot of the rootvg volume group, so a clean restore rebuilds the operating system, its tunables, installed filesets, and the root file systems exactly as they were captured. The p690 (POWER4) and p595 (POWER5) are long past their service life, so treat the legacy key sequences below as a faithful reference and apply the same logic on newer POWER8, POWER9, and POWER10 frames managed by a current HMC.

What a mksysb image actually contains

A mksysb is not a generic file copy. It is a structured archive that captures everything needed to recreate the system volume group and boot from it. Understanding the layout makes both backup and restore AIX operations far less mysterious.

• Boot image — a bootable kernel and a reduced RAM file system so the media can start the machine without an existing OS.
• BOS install / control files — the image.data and bosinst.data that describe logical volumes, file system sizes, and install behaviour.
• rootvg data — a backup-format archive of every mounted JFS/JFS2 file system in rootvg (typically /, /usr, /var, /tmp, /home, and /opt).

Crucially, a mksysb only backs up rootvg. Application data living in separate volume groups (for example datavg or appvg) is not included and must be protected separately with savevg, a database-native dump, or your enterprise backup tool. A restore that brings back the OS but loses the data VG is a half-recovery, so plan both halves together.

Creating the mksysb backup (the source of the restore)

You cannot restore what you never captured, so reliable scheduled backups come first. In many shops a cron job writes a fresh image to a local file system such as /mkdvd/<hostname> on a regular cadence. A clear, dated naming convention makes it obvious which image you are about to restore.

A common pattern names each file <hostname>_mksysb_<weekday>DDMonYYYY, for example lipdv02_mksysb_Thu08Feb2007. Listing the backup directory shows the image and its size:

root@lipdv02:/mkdvd/lipdv02 # ls -l
-rw-r----- 1 root sys 4761446400 Feb 08 11:33 lipdv02_mksysb_Thu08Feb2007

To generate an image to a file by hand, use the mksysb command. The -i flag regenerates image.data so the backup reflects the current logical-volume layout, and -X lets the boot file system grow if needed:

1. Make sure there is enough free space in the target file system (a full rootvg image can be several gigabytes).
2. Run the backup:

   mksysb -i -X /mkdvd/lipdv02/lipdv02_mksysb_$(date +%a%d%b%Y)

3. Verify the archive is readable and bootable:

   lsmksysb -l -f /mkdvd/lipdv02/lipdv02_mksysb_Thu08Feb2007

If your restore target is optical media, burn the image to DVD-RAM with mkdvd (or mkcd for CDs). On modern systems, prefer a NIM (Network Installation Management) master so partitions can boot and restore over the network with no physical media at all.

Problem: a partition is down and must be rebuilt

The scenario this procedure solves is a partition whose rootvg is gone or unbootable — a failed disk pair, a corrupted OS, a botched upgrade, or a brand-new LPAR that needs the same gold image. The fix is to boot the LPAR from the mksysb media and let the BOS installer lay the captured image back down onto the target disks.

Before you start, confirm three things: you have the correct, recent mksysb for that exact host; you know which physical disks should receive the install (usually the mirrored pair hdisk0 and hdisk1); and you have console access to the partition through the HMC. Getting the disk selection wrong is the one truly destructive step, so slow down there.

Step-by-step: restore AIX from a system backup

The exact menu numbers below match the POWER4 p690 and POWER5 p595 firmware. Newer frames present the same logical choices (SMS, boot device, maintenance mode, install from backup) with slightly different numbering, so read each screen rather than memorising keystrokes.

1. Insert the AIX LPAR mksysb backup DVD-RAM into the p690 or p595 DVD-RAM drive.
2. On the HMC, activate the correct profile for the logical partition you are rebuilding, opening a terminal/console window so you can watch it boot.
3. When you hear the beep or see the firmware banner, press 1 to enter the SMS Menu. The banner typically reads:

   1 = SMS Menu          5 = Default Boot List
   8 = Open Firmware     6 = Stored Boot List

4. Open the boot-device options: press 7 on a p690 or 5 on a p595 to Select Boot Options.
5. Press 1 for Select Install or Boot a Device.
6. Press 3 for the CD/DVD device type.
7. Press 1 for the SCSI media type.
8. Select the optical adapter for your frame: U1.9-P1-I10/Z1 on the p690, or U5791.001.99203 NY-P1-C10-T1 on the p595. (Your physical location codes will differ — match the adapter wired to the DVD drive.)
9. Press 1 for the SCSI CD-ROM device.
10. Press 3 for Service Mode Boot (a normal boot, not the install task).
11. Press 1 to exit System Management Services and let the partition boot from the DVD.
12. When prompted, press 1 and Enter to use this terminal as the system console.
13. Press 1 and Enter to choose English during the install.
14. At the installation/maintenance menu, press 3 to Start Maintenance Mode for System Recovery.
15. Press 4 to Install from a System Backup.
16. Choose the backup device: press 1 on a p690 or 2 on a p595 to select the optical device (device name cd0, path /dev/cd0) that holds the mksysb, then press Enter.
17. Press 1 for the disks where AIX will be installed.
18. Select the target disks — typically 1 - hdisk0 and 2 - hdisk1 for a mirrored install. Double-check these are the OS disks and contain nothing you need, because they will be overwritten.
19. Press 0 to continue with the choices shown above.
20. Press 0 again to begin the install using the current settings and lay the Base OS backup down onto the selected disks.

The installer now restores the AIX image from the DVD to the hard disks and reboots automatically when the restore finishes. From a NIM master the same flow runs without media: in SMS you choose the network adapter instead of the CD/DVD device and the master streams the mksysb resource over the LAN.

Common pitfalls when you restore AIX

Most failed recoveries trace back to a handful of avoidable mistakes. Watch for these before and during the restore.

• Wrong target disks. Selecting the data disks instead of hdisk0/hdisk1 destroys application data. Identify the OS disks beforehand with lspv and bootinfo -b while the system is still alive.
• Stale or wrong-host image. A mksysb is host-specific. Restoring last quarter's image, or another machine's image, leaves you with old data or a hostname/IP mismatch. Always confirm the filename date and hostname.
• Disk-size mismatch. If the new disks are smaller than the originals, the captured logical volumes may not fit. Use the shrink option in the install settings, or edit image.data so logical volumes are sized to fit the new layout.
• Forgetting non-rootvg data. The mksysb restores only rootvg. After the OS is back, you still need to import the data volume groups with importvg (and restore any savevg archives).
• Network identity on a clone. When you use one gold image to build several LPARs, the restored system inherits the source hostname and IP. Boot to maintenance mode or set RECOVER_DEVICES=no so you can re-key the network on first boot.
• Wrong device in SMS. Picking the wrong SCSI adapter or media device just hangs the boot. Match the physical location code to the slot the DVD drive actually lives in.

Verification: confirm the restore succeeded

A reboot at the AIX login prompt is encouraging but not proof. Run a short post-restore checklist before handing the system back to users.

1. Confirm AIX level and identity:

   oslevel -s
   hostname
   uname -a

2. Check the volume groups, mirroring, and file systems:

   lsvg -o
   lsvg -l rootvg
   df -g

   Every expected rootvg file system should be mounted with sane free space.
3. Verify both copies of a mirrored rootvg are synced (no stale partitions):

   lsvg -l rootvg          # LV STATE should read syncd, not stale
   

   If any LV shows stale, run syncvg -v rootvg.
4. Confirm the bootlist points at the restored disks:

   bootlist -m normal -o

5. Bring back and verify data volume groups:

   importvg -y datavg hdisk2
   varyonvg datavg
   lsvg -l datavg

6. Check networking and services:

   ifconfig -a
   netstat -rn
   lssrc -a | grep -i active

7. Review the boot and error logs for anything unexpected:

   alog -o -t boot | tail
   errpt | head

Only once identity, storage, mirrors, networking, and key services all check out should you declare the restore AIX operation complete.

Modern equivalents for retired POWER hardware

The p690 and p595, and the AIX 5.x releases that typically ran on them, are end of life and unsupported. The mksysb concept, however, is still the backbone of AIX recovery on current hardware, so the workflow translates almost one to one.

On modern frames the best practice is a NIM master holding mksysb resources, SPOT, and lpp_source, letting you push a recovery to any client LPAR over the network. The on-frame steps are identical in spirit: activate the profile, enter SMS, choose the boot source (network instead of DVD), boot to maintenance mode, install from system backup, pick the disks, and verify.

Restore AIX safely: a quick mental model

Boil the whole procedure down to five moves and it is hard to get lost: capture a current mksysb, boot the LPAR from that backup via SMS, enter maintenance mode, install from the system backup onto the correct disks, then verify identity, storage, and services. Keep the data volume groups in a separate backup track and you have a recovery plan that survives almost any rootvg failure.

Key Takeaways

• A mksysb is a bootable snapshot of rootvg only — back up data volume groups separately with savevg or a native tool.
• Restore by booting the LPAR from the mksysb media via the SMS menu, then choosing Maintenance Mode and Install from a System Backup.
• The single destructive step is target-disk selection — confirm hdisk0/hdisk1 are the OS disks before you continue.
• Always verify after a restore: oslevel -s, lsvg -l rootvg (syncd, not stale), bootlist, networking, and services.
• p690/p595 are EOL; apply the same mksysb logic on POWER8/9/10 with a NIM master for media-free network recovery.

Frequently Asked Questions

Does a mksysb back up all my data?

No. A mksysb captures only the rootvg volume group — the operating system and root file systems. Application and database data in other volume groups must be protected separately with savevg, a database dump, or your enterprise backup software, then re-imported with importvg after the OS restore.

How do I boot an AIX LPAR into SMS to start a restore?

Activate the partition profile from the HMC with a console open, then press 1 as soon as you hear the beep or see the firmware banner. That enters the SMS menu, where you select the boot device (CD/DVD or network) the mksysb lives on.

Can I use one mksysb image to build several servers?

Yes — cloning from a gold image is common. Because the image carries the source hostname, IP, and device data, restore with RECOVER_DEVICES=no or boot to maintenance mode afterward so you can reset the network identity, ODM device entries, and licensing on each new LPAR.

Is this procedure still valid now that the p690 and p595 are retired?

The exact SMS key numbers are specific to those POWER4/POWER5 frames, but the workflow is unchanged on supported POWER8/9/10 hardware running AIX 7.2 or 7.3. Modern shops typically restore from a NIM master over the network instead of DVD-RAM, following the same SMS, maintenance-mode, install-from-backup sequence.

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