Clustered Disk Drive Letter Unexpectedly Changes (815616)

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

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.

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 How to Obtain the Latest Windows 2000 Service Pack

Hotfix Information

A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem. This fix may receive additional testing. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Windows 2000 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:

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

NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The typical support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

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

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 The Datacenter Program and Windows 2000 Datacenter Server Product