Storage Optimizer memory use increases when it runs on thin provisioned LUNs

Kehtib: Windows Server 2012 R2 DatacenterWindows Server 2012 R2 StandardWindows Server 2012 Datacenter

Symptoms


Consider the following scenario:
  • You have a server that's running Windows RT 8.1, Windows 8.1, Windows Server 2012 R2, Windows RT, Windows 8, or Windows Server 2012.
  • You have one or more thin provisioned logical unit numbers (LUNs) that are using a slab size that's smaller than 8 megabytes (MB).
  • You run the Storage Optimizer (Defragsvc.exe, previously known as the Disk Defragmenter tool) either manually or by a scheduled task.

In this scenario, the memory that's used by the Storage Optimizer continually increases over time. And in some environments, the system may become unresponsive or restart unexpectedly.

Resolution


To resolve this issue, install update rollup 2975719 or update rollup 2975331, or install the hotfix that is described in this article.

Update information

For more information about how to obtain this update rollup package, click the following article number to view the article in the Microsoft Knowledge Base:
2975719 August 2014 update rollup for Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2

2975331 August 2014 update rollup for Windows RT, Windows 8, and Windows Server 2012

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 this specific problem.

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, submit a request to 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.

Prerequisites

To apply this hotfix, you must first install the update 2919355 on Windows 8.1 or Windows Server 2012 R2. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

2919355 Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 Update April, 2014

Registry information

To use the hotfix in this package, you do not have to make any changes to 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.

Workaround


To temporarily work around this problem, either disable the Storage Optimizer "Optimize drives" service or exclude the thin provisioned LUNs from the scheduled task.

Status


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

More Information


There's no need to run Storage Optimizer on thin provisioned LUNs that use an allocation size (also known as slab size) of less than 8 MB. Thin provisioned LUNs that have a smaller slab size manage space more efficiently, and the benefits of defragmenting them are not as great.

When you run the Storage Optimizer with the Analyze switch at a command prompt or a PowerShell prompt (for example, defrag g: /a or Optimize-Volume -Analyze g –Verbose) on a thin provisioned LUN that's using a small slab size, the command does not execute, and you receive the following error message:

Neither Slab Consolidation nor Slab Analysis will run if slabs are less than 8 MB.

This is expected behavior because slab consolidation and slab analysis has been disabled on thin provisioned LUNs that have a slab size of less than 8 MB.

For more information, see What's new in defrag for Windows Server 2012/2012R2.