Article ID: 815616 - Last Review: February 21, 2007 - Revision: 2.9

Clustered Disk Drive Letter Unexpectedly Changes

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SYMPTOMS

A physical disk resource may intermittently go offline on your Windows 2000-based server cluster. When this symptom occurs, the following information is recorded in the Cluster log file (Cluster.log):

00000718.0000093c::2002/12/30-06:45:15.657 Physical Disk: [PnP] DriveLetterChange: F => ?
00000718.0000093c::2002/12/30-06:45:15.657 Physical Disk <Disk F:>: Mountie[0]: 1, let=?, start=7E00, len=12CAA000.
00000718.0000093c::2002/12/30-06:45:15.657 Physical Disk <Disk F:>: PokeDiskResource: Volumes not ready, error 2
00000718.0000093c::2002/12/30-06:45:15.657 Physical Disk: PnP Event GUID_IO_VOLUME_NAME_CHANGE for ? (Partition1) received.
00000718.0000093c::2002/12/30-06:45:15.673 Physical Disk: [PnP] DriveLetterChange: ? => ?
00000718.0000093c::2002/12/30-06:45:15.673 Physical Disk: PnP Event GUID_IO_VOLUME_NAME_CHANGE for ? (Partition1) received.
00000718.0000093c::2002/12/30-06:45:15.704 Physical Disk <Disk F:>: Mountie[0]: 1, let=?, start=7E00, len=12CAA000.
00000718.0000093c::2002/12/30-06:45:15.704 Physical Disk <Disk F:>: PokeDiskResource: Volumes not ready, error 2

Also, you may receive one or more "Delayed Write Failed" events that are similar to the following in the Event Viewer System log:

Date:     date        Source:   Ftdisk
Time:     time        Category: None
Type:     Error         Event ID: 50
User:     N/A
Computer: computername

Description:
{Delayed Write Failed} Windows was unable to save all the data for the file \Device\HarddiskVolumeX.
The data has been lost. This error may be caused by a failure of your computer hardware or network connection.
Please try to save this file elsewhere.

Data:
0000: 00040000 005e0001 00000000 80040032
0010: 00000000 00000000 00000000 00000000
0020: 00000000 00000000 c000000e

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CAUSE

This problem occurs because an unexpected PnP event may trigger a drive letter change for a physical disk resource in a Windows 2000 server cluster, taking the disk off-line. When this occurs, programs can no longer access this disk, and some corrective action might be required to restore access. This action is dependent on the programs that are contained in the affected group, and may include one or more of the following:

Restarting the resource or group.
Restarting the Microsoft Cluster Services.
Restarting the computer.

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RESOLUTION

Service Pack Information

To resolve this problem, obtain the latest service pack for Microsoft Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

260910 (http://support.microsoft.com/kb/260910/EN-US/ ) How to Obtain the Latest Windows 2000 Service Pack

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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 Web site:

http://support.microsoft.com/contactus/?ws=support (http://support.microsoft.com/contactus/?ws=support)

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. The Global version of this fix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

   Date         Time   Version        Size    File name
   -------------------------------------------------------
   25-Jun-2002  11:33  5.0.2195.5912  34,384  Classpnp.sys

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STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Microsoft Windows 2000 Service Pack 4.

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MORE INFORMATION

The unexpected PnP event occurs because of a synchronization problem in a PnP driver, where the size of the affected hard disk partition is computed in sectors, and then in bytes. A concurrent query on the hard disk partition size that occurs between the times that the partition is computed in sectors, and when it is again computed in bytes, returns the partition size in sectors, but is interpreted as bytes. This causes the operating system to determine that the hard disk was removed, with the resultant loss of the physical disk resource. The c000000e entry in the Data portion of Event ID 50 corresponds to 0xC000000E STATUS_NO_SUCH_DEVICE, indicating that the hard disk no longer appears.

This update removes the time window between the partition calculations. The partition size will always be returned in bytes.

For additional information about how to obtain a hotfix for Windows 2000 Datacenter Server, click the article number below to view the article in the Microsoft Knowledge Base:

265173 (http://support.microsoft.com/kb/265173/EN-US/ ) The Datacenter Program and Windows 2000 Datacenter Server Product

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