Exalytics: Starting Or Stopping A VM Guest Is Very Slow (15-30 minutes) And Hangs The XM Interface

Asset ID:	1-72-2078374.1
Update Date:	2015-11-20
Keywords:

Solution Type Problem Resolution Sure

Solution 2078374.1 : Exalytics: Starting Or Stopping A VM Guest Is Very Slow (15-30 minutes) And Hangs The XM Interface

Applies to:

Exalytics In-Memory Machine X4-4 - Version All Versions and later
Oracle Exalytics Software - Version 2.0.0.0.0 and later
Information in this document applies to any platform.

Symptoms

After doing a new install of R2 with OEL 6, restarting the guests is very slow, taking 15-30 minutes, and hanging the xend and xm interface on Dom0.

Cause

This is caused by the memory scrubbing delay which happens on all VM stops and restarts, as described in the following two bugs:

1. Bug 21930548 - PERFORMANCE ISSUE WITH DOM0/XEND PROCESS WHEN STOPPING/RESTARTING VM GUESTS
2. Bug 21885078 - UNACCEPTABLE PERFORMANCE OF DOM0/XEND PROCESS WHEN STOPPING/RESTARTING VM GUESTS

Solution

Download the following RPM's:

1. http://public-yum.oracle.com/repo/OracleVM/OVM3/latest/x86_64/getPackage/xen-4.1.3-25.el5.127.68.x86_64.rpm
2. http://public-yum.oracle.com/repo/OracleVM/OVM3/latest/x86_64/getPackage/xen-devel-4.1.3-25.el5.127.68.x86_64.rpm
3. http://public-yum.oracle.com/repo/OracleVM/OVM3/latest/x86_64/getPackage/xen-tools-4.1.3-25.el5.127.68.x86_64.rpm

Run "yum install xen*.rpm" on the dom0, in the directory of the downloaded RPMs, to install them (don't use "rpm -i" or "rpm -U").

The slow performance is related to memory-scrubbing, that is necessary for a proper restart. The amount of time required is directly related to amount of memory used by the VM (in this case 300gb). However, these RPM's eliminate the hanging of the the dom0 Xend process, during the restart, by enabling Xend and memory scrubbing to occur in parallel.

References

<BUG:21930548> - PERFORMANCE ISSUE WITH DOM0/XEND PROCESS WHEN STOPPING/RESTARTING VM GUESTS
<BUG:21885078> - UNACCEPTABLE PERFORMANCE OF DOM0/XEND PROCESS WHEN STOPPING/RESTARTING VM GUESTS

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