Performance slower in Oracle VM when compared with Baremetal

(Doc ID 2080843.1)

Last updated on DECEMBER 14, 2017

Applies to:

Oracle VM - Version 2.1 to 3.3.3 [Release OVM21 to OVM33]
Linux x86-64

Symptoms

Performance issues were noticed during the process of migrating applications from X4 bare metal (BM) to X5 virtualised environments (VM). During testing it was discovered that certain data loads run slower in VM when compared with BM. The databases are placed in 2-node RAC environments.

Analysis of the issue has shown that the issue can be reproduced only when the CLUSTER_DATABASE parameter is set to TRUE, regardless of the number of RAC instances running.

With CLUSTER_DATABASE=FALSE, the VM performance was comparable with that of the BM. Once this was identified, subsequent analysis was performed in the VM environment with only a single instance running. This problem is an Oracle VM issue affecting communication at a particular layer and not Exadata specific. This issue is observed after migrating to Oracle VM.

Example: running Oracle*Forms in an old iAS 10g after an OVM migration (EBS environment)

 

Changes

The only Change is X4 bare metal (BM) to X5 virtualised environments (VM). In this case the change of Exadata environment (X4 -> X5) is not relevant because the issue is specific to Oracle VM.

Cause

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