Disk-based cache at critical capacity (SharePoint Server 2010)

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Applies to: SharePoint Server 2010, SharePoint Foundation 2010

Alert Name:   Disk-based cache at critical capacity

Event ID:   None

Summary:   To save time accessing frequently used static files, Microsoft SharePoint Server 2010 uses the disk-based cache to store these files on the disk of the front-end Web server instead of accessing these files directly from the database server. Farm administrators can configure settings for the cache by modifying the Web.config file on each front-end Web server.

This alert indicates that the disk-based cache is too full to serve files efficiently. When the disk-based cache is full, it will start compacting — that is, removing files from the cache to free up space. Compacting is a resource-intensive process that might affect the performance of the front-end Web server.

Symptoms:   The Blob Cache fill ratio performance counter threshold has been exceeded.

Cause:   The configured size for the disk-based cache is smaller than the total size of frequently accessed files for the Web application.

Resolution:   Increase the size of the disk-based cache

  1. For information about how to configure the Web.config file, see Configure cache settings for a Web application (SharePoint Server 2010).

Resolution:   Manually flush the disk-based cache by using Windows PowerShell

  1. Verify that you meet the following minimum requirements: See Add-SPShellAdmin.

  2. On the Start menu, click All Programs.

  3. Click Microsoft SharePoint 2010 Products.

  4. Click SharePoint 2010 Management Shell.

  5. At the Windows PowerShell command prompt, type the following command:

    Add-PSSnapin Microsoft.SharePoint.Powershell
Write-Host "Flush the Blob Cache for the application containing the specified site collection"
$site = Get-SPSite -Identity <URL>
[System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint.Publishing")
Write-Host "Flushing..."
[Microsoft.SharePoint.Publishing.PublishingCache]::FlushBlobCache($site.WebApplication)
Write-Host "Flushed Cache for:" $site.WebApplication

    Where:

    • <URL> is the URL in the event details.

Resolution:   Change the file types to be stored by the disk-based cache

  1. For information about how to configure the Web.config file, see Configure cache settings for a Web application (SharePoint Server 2010)