Troubleshooting
Problem
InfoSphere Information Server customers upgrade their installations to RedHat Linux 6 and later notice that Parallel Engine jobs are using more memory. The increased usage has been most visible for InfoSphere Information Services Director workloads but it applies to all Parallel Engine jobs.
Symptom
The increased memory usage is caused by the Linux kernel ‘Huge Page’ feature. This feature has been in Linux for years, but it was normally not enabled. Starting with Red Hat Enterprise Linux 6, the Huge Page feature is enabled by default ("Transparent Huge Pages") and customers who upgrade to Red Hat 6 are likely to see a 30% or more increase in memory usage during parallel job execution. The Huge Page feature is intended to improve performance on systems with very large amounts of RAM, but memory usage will increase unless the Linux kernel is properly tuned.
Resolving The Problem
The performance costs and benefits of the Huge Page feature have been analyzed.
| At this time, IBM recommends that customers using the DataStage Parallel Engine on Linux 6.x turn off Huge Pages. Customers should review the Huge Page settings with their system administration staff and disable the Transparent Huge Page feature. |
https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Performance_Tuning_Guide/s-memory-transhuge.html
and
| https://access.redhat.com/site/solutions/422283 |
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Document Information
Modified date:
16 June 2018
UID
swg21664196