Microsoft KB Archive/925477

= Event IDs 1100, 1101, and 1102 are logged every time that the Virtual Server service starts in Virtual Server 2005 R2 =

Article ID: 925477

Article Last Modified on 10/6/2006

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APPLIES TO


 * Microsoft Virtual Server 2005 R2 Standard Edition
 * Microsoft Virtual Server 2005 R2 Enterprise Edition

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SYMPTOMS
On a computer that is running Microsoft Virtual Server 2005 R2, the following events are logged every time that the Virtual Server service starts:

Event ID 1100

Event Type: Information

Event Source: Virtual Server

Event Category: Virtual Server

Event ID: 1100

Date:

Time:

User: NT AUTHORITY\NETWORK SERVICE

Computer:

Description: The host machine has multiple NUMA nodes.

Event ID 1101

Event Type: Information

Event Source: Virtual Server

Event Category: Virtual Server

Event ID: 1101

Date:

Time:

User: NT AUTHORITY\NETWORK SERVICE

Computer:

Description: Node  has   megabytes of available memory.

Note This event may appear many times. In this event,  represents an integer, such as 2 or 3.

Event ID 1102

Event Type: Warning

Event Source: Virtual Server

Event Category: Virtual Server

Event ID: 1102

Date:

Time:

User: NT AUTHORITY\NETWORK SERVICE

Computer:

Description: Some nodes on this machine do not have local memory. This can cause virtual machines to run with degraded performance.

You may experience this problem on a computer that has multiple dual-core processors. In event ID 1101,  represents the second core of a particular dual-core processor.



CAUSE
This problem occurs if local memory is unavailable to the second core of each physical processor. Virtual Server uses the operating system nonuniform memory access (NUMA) APIs to determine whether nodes are populated with memory.



RESOLUTION
To resolve this problem, local memory must be added to or presented to the second core of each physical processor. These second cores are represented by Node 2, Node 3, and so on in the description area of event ID 1101.

The ability to add local memory to these processor cores is a feature of the computer BIOS. To enable this feature, you may have to update the computer BIOS.



MORE INFORMATION
When the computer starts, the BIOS builds the Static Resource Affinity Table (SRAT). This table passes the NUMA topology to the operating system.

The operating system uses the information that is provided by the SRAT to support the following NUMA features:
 * To provide the default processor affinity settings for processes and for threads
 * To make sure that threads are rescheduled to a processor in the same NUMA node whenever possible
 * To make sure that memory is allocated locally wherever possible
 * To provide an API that application software can use to obtain the NUMA topology of the system

Note Virtual Server uses these APIs to determine whether nodes are populated with memory.

Generally, you do not experience a decrease in performance if the NUMA ratio of the computer is between 1.0 and 1.5. You may experience performance issues if the NUMA ratio is 3.0 or greater. The NUMA ratio corresponds to the time that a processor node requires to access &quot;remote&quot; memory compared to the time that the processor node requires to access &quot;local&quot; memory. Remote memory is memory that is assigned to a different node. Local memory is memory that is assigned to the local node. If each node is on a separate physical processor, you may have to add local memory to each node.

Keywords: kbtshoot kbeventlog kbprb KB925477

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