Flashes (Alerts)
Abstract
IBM has identified an issue with AFM in IBM Spectrum Scale V4.2.0.0 through 4.2.0.2 levels when the AFM cache reads the HSM migrated files from home (running IBM Spectrum Scale V4.2 or later) as a sparse file. This issue may cause the cache to have undetected data corruption and may return incorrect data (all zeros) to an application on read.
Content
Problem Summary:
As a result of incorrect sparseness information detection on an HSM migrated files at home, the AFM cache may incorrectly read the migrated file from home as a fully sparse file.
Users affected:
Only files greater than 128 MB that have been migrated to tape on the Home side will be affected, and only when all three of the following conditions are met:
- Users are running IBM Spectrum Scale 4.2.0.0, 4.2.0.1 or 4.2.0.2 at the AFM Home cluster.
- HSM migration is enabled on the Home side of an AFM fileset relationship.
- Home is enabled for AFM (the mmafmconfig command was run on target path).
Recommendations:
- Any customer planning to use AFM with the affected IBM Spectrum Scale 4.2 code levels installed (see above) should either (a) not enable HSM migration on the Home side of an AFM fileset relationship; or (b) wait until they are able to install IBM Spectrum Scale 4.2.0.3, available on Fix Central at https://www-945.ibm.com/support/fixcentral/swg/selectFixes?parent=Software%2Bdefined%2Bstorage&product=ibm/StorageSoftware/IBM+Spectrum+Scale&release=4.2.0&platform=All&function=all, or apply an efix for APAR IV83848 by contacting IBM Service.
- If you believe that your GPFS file system may be affected by this issue, you should contact IBM Service as soon as possible for further guidance and assistance.
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Document Information
Modified date:
25 September 2022
UID
ssg1S1005766