Notification
Risk classification
HIPER (High Impact and/or Pervasive)
Risk categories
Severe Performance Impact
Subcategories for Informational notifications
Troubleshooting & Fixes
Affected Domain
AIX 7.3 TL3 or VIOS 4.1.1
Abstract
Unexpected performance loss on AIX 7.3 TL3 or VIOS 4.1.1 with offload_iodone enabled
Description
LPARs running AIX 7.3 TL3 or VIOS 4.1.1 with the default setting of offload_iodone enabled may see lower than expected I/O performance.
This is only seen if the LPAR is running on: Power8; Power9 not in "POWER9" mode; or Power10 not in "default" or "POWER10" mode.
This is only seen if the LPAR is running on: Power8; Power9 not in "POWER9" mode; or Power10 not in "default" or "POWER10" mode.
Recommended Action
Only if affected, as described above:
- Install the below ifix, which requires a reboot to be active.
- Disable offload_iodone until the next reboot with:
schedo -o offload_iodone=0Note for VIOS this will require entering the root shell with oem_setup_env .
Affected AIX Levels and Recommended Fixes
| Minimum Affected Level | Maximum Affected Level | Fixing Level | Interim Fix |
|---|---|---|---|
| AIX 7300-03-00 bos.mp64 7.3.3.0 |
AIX 7300-03-00 bos.mp64 7.3.3.0 |
AIX 7300-03-01 IJ53641 |
iFix |
| VIOS 4.1.1.0 bos.mp64 7.3.3.0 |
VIOS 4.1.1.0 bos.mp64 7.3.3.0 |
VIOS 4.1.1.10 IJ53641 |
iFix |
| Note: Installation of this fix requires a reboot. | |||
This table describes which active levels are affected and where to obtain fixes.
Before the APAR fix is available, an interim fix (iFix) is available for each affected level.
The available interim fixes might apply only to the latest Service Packs. If a custom interim fix is required, contact IBM Support.
The interim fixes can be downloaded using HTTPS.
Verify you have retrieved the fixes intact:
The checksums below were generated using the "openssl dgst -sha256 [filename]" command as the following:
| openssl dgst -sha256 | filename |
| 399be3f953012408a759f09b35051844d84441bf3d720f5e47b102824ee2ac2f |
IJ53641s0a.250324.AIX73TL03SP00.epkg.Z
IJ53641s0a.250324.VIOS4.1.1.0.epkg.Z |
Date first published
10 April 2025
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Document Information
Modified date:
11 April 2025
UID
ibm17230030