IBM Support

VIOS Updates: Harnessing the Power of Alternate Disk Update

How To


Summary

Updateios command updates the Virtual I/O Server to the latest maintenance level. With the release of VIOS 4.1.2.00, a significant enhancement has been introduced: support for updateios on an alternate disk. This feature is designed to improve system availability and reduce risk during updates.

Objective

  • High Availability: Your VIOS stays online during the update.
  • Risk Reduction: Updates happen in isolation, minimizing downtime.
  • Easy Recovery: Simply clean the alternate disk, original root disk stays intact.

 

Steps

How It Works

You can run the updateios command with a new option:

updateios -dev <Media> -install -accept -altdisk <targetDisks>
altdisk               Specifies to apply the update on alternate disk(s).
targetDisks           One or more colon separated list of disks which must be unused & free.

 

Example:

updateios -dev /home/padmin/UPDATE -install -accept -altdisk hdisk1

 

After the Update

Once the update completes successfully, you can change the bootlist to boot VIOS from the alternate disk by running the following command. 

bootlist -m normal -o <alternate_disk#>
 
 
 

Additional Information

Recovery Steps in Case of Failure

If the update on the alternate disk fails:

  1. Do not change the bootlist — keep the system booting from the original disk.
  2. Check the console logs of updateios for any errors.
  3. Run $ alt_root_vg -remove to delete the altinst_rootvg Volume Group.
  4. Re-run updateios after fixing the issues. Choose a different alternate disk or clean and reuse the used one. You will have to run “$ cleandisk -f -c alternate_disk” command to clean disk to mark it as free. 
 

Traditional vs Alternate Disk Update

Feature

Traditional Update

Alternate Disk Update

Risk of downtime

High

Low

Recovery complexity

High

Minimal


 

Document Location

Worldwide

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Document Information

Modified date:
29 July 2026

UID

ibm17281754

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