Large version store size causes high CPU usage on a computer that is running Windows Server 2008 R2

When a transaction in the Active Directory runs for a long time on a computer that is running Windows Server 2008 R2, the version store becomes very large. Additionally, hash table chains become very long when the version store is very large. In this situation, the Extensible Storage Engine (ESE) processes all version store hash tables. Therefore, high CPU usage occurs in the Lsass.exe process.

For example, if the version store is 1.12 gigabytes (GB), there will be 17,500 hash tables whose size is 64 kilobytes (KB).

Notes

• This issue generally occurs when the max version store size is increased to a high value by the following NTDS Parameters registry setting:
  EDB max ver pages (increment over the minimum)
  
  This registry setting is outlined in the following Microsoft Knowledge Base article:
  974803 The domain controller runs slower or stops responding when the garbage collection process runs
• The version store hash table is hardcoded to 64 KB regardless of the size of the version store itself.
• The number of version store hash tables that is compared to version store size can cause a performance bottleneck. If the hash table chains are processed frequently, high CPU usage issue occurs.
• Extensible Storage Engine (ESE), formally known as JET Blue, is an Indexed Sequential Access Method (ISAM) data storage technology that forms the core of the Active Directory. ESE enables applications to store and retrieve data by using indexed and sequential access. ESE provides transactional views of the database. Objects that are changed in a transaction are temporarily copied so that two views of the object can be provided: one to the thread inside that transaction and one to threads in other transactions. This copied data must remain as long as any two transactions in the process have different views of the object. Version store is used to store these temporary copies. The version store requires contiguous virtual address space; therefore it has a size limit.
  

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing the problem described in this article. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft website: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

After you install the update, the hash table size will change according to the version store size. This improves performance

For example, if the version store is 1.12 GB, the hash table size is 10 megabytes (MB).

Prerequisites

To apply this hotfix, you must be running Windows Server 2008 R2 or Windows Server 2008 R2 Service Pack 1 (SP1). For more information about how to obtain a Windows Server 2008 R2 service pack, click the following article number to view the article in the Microsoft Knowledge Base:

Registry information

To apply this hotfix, you do not have to change the registry.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The global version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.

Windows Server 2008 R2 file information notes

Important Windows 7 hotfixes and Windows Server 2008 R2 hotfixes are included in the same packages. However, hotfixes on the Hotfix Request page are listed under both operating systems. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows 7/Windows Server 2008 R2" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each hotfix applies to.

• The files that apply to a specific product, milestone (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:

  Version	Product	Milestone	Service branch
  6.1.760 1.22xxx	Windows Server 2008 R2	SP1	LDR

• The MANIFEST files (.manifest) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2008 R2" section. MANIFEST files and the associated security catalog (.cat) files, are extremely important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.

For all supported x64-based versions of Windows Server 2008 R2

For all supported IA-64-based versions of Windows Server 2008 R2

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:

Additional file information

Additional file information for Windows Server 2008 R2

Additional files for all supported x64-based versions of Windows Server 2008 R2

Additional files for all supported IA-64-based versions of Windows Server 2008 R2