Microsoft KB Archive/903650

= Extended maintenance mode functionality for cluster physical disk resources in Windows Server 2003 =

Article ID: 903650

Article Last Modified on 3/28/2007

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APPLIES TO

 Microsoft Windows Server 2003 Service Pack 1, when used with:  Microsoft Windows Server 2003, Datacenter Edition (32-bit x86)

 Microsoft Windows Server 2003, Enterprise Edition (32-bit x86)

 Microsoft Windows Server 2003, Datacenter Edition for Itanium-Based Systems

 Microsoft Windows Server 2003, Enterprise Edition for Itanium-based Systems</li></ul> </li> Microsoft Windows Server 2003, Datacenter x64 Edition</li> Microsoft Windows Server 2003, Enterprise x64 Edition</li> Microsoft Windows Server 2003 R2 Enterprise x64 Edition</li> Microsoft Windows Server 2003 R2 Datacenter x64 Edition</li></ul>

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SUMMARY
This article describes an update to the maintenance mode feature for cluster physical disk resources in Microsoft Windows Server 2003. This update provides extended functionality when you use maintenance mode to perform administrative and maintenance tasks in a clustered environment. For example, this update lets you perform a Volume Shadow Copy Service (VSS) recovery on a disk resource without taking down all dependent resources and their services.

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Overview of Windows Server 2003 cluster management
Server clusters introduce an environment where disks are managed differently than they are in a stand-alone server environment. For example, in server clusters, multiple initiators do not access a single disk. Clustering requires that only one server or only one node access a Logical Unit Number (LUN) at a time. This configuration guarantees that another server does not try to write to the same disk. If more than one server writes to the same disk, data on the disk may become corrupted.

Health monitoring checks on a cluster-managed LUN
A series of health monitoring checks are performed on cluster-managed LUNs to make sure that a LUN is available. If any one of these checks fail, the Cluster service assumes that there is a problem with the LUN and takes recovery action. Recovery actions may include the following:
 * Trying to restart the resources and to mount the disk again on that same node.
 * Assuming failover ownership of the disk.
 * Trying to bring the disk online on another node in the cluster.

The following checks are performed on any disk that is online and that is managed by the cluster:
 * File system level checks

At the file system level, the Physical Disk resource type performs the following checks:
 * LooksAlive

By default, a brief check is performed every 5 seconds to verify that a disk is still available. The LooksAlive check determines whether a resource flag is set. This flag indicates that a device has failed. For example, a flag may indicate that periodic reservation has failed. The frequency of this check is user definable.
 * IsAlive

A complete check is performed every 60 seconds to verify that the disk and the file system, or systems, can be accessed. The IsAlive check effectively performs the same functionality as a dir command that you type at a command prompt. The frequency of this check is user definable.
 * Device level checks

At the device level, the Clusdisk.sys driver performs the following checks:
 * SCSI Reserve

Every 3 seconds, a SCSI Reserve command is sent to the LUN to make sure that only the owning node has ownership and can access that drive.
 * Private Sector

Every 3 seconds, the Clusdisk.sys driver performs a read and write operation to sector 12 on the LUN to make sure that the device is writeable.

Note The timing of these device level checks is not user definable. The Clusdisk.sys driver is very dependent on this timing for its algorithm when the Clusdisk.sys driver arbitrates for shared disks. If you modify or suppress this timing functionality, you affect the core multi-initiator management functionality of the cluster.

Maintenance mode in Windows Server 2003 Service Pack 1
Windows Server 2003 Service Pack 1 includes a new feature that is called maintenance mode. This mode lets you perform certain administrative and maintenance tasks in a clustered environment. These tasks must be performed on shared clustered disks. These shared clustered disks may require another application or mechanism to obtain an exclusive lock on a disk. When you perform administrative and maintenance tasks, a disk may appear in a regular online state, but health monitoring may be temporarily suppressed. Also, the disk may not be available to clients.

For example, if you type chkdsk /f on a disk that is managed and monitored by the cluster, the disk is locked for exclusive use to examine the consistency of the disk. This behavior may cause health monitoring checks for that disk to fail if the CHKDSK command takes longer then the time-out period that is set for the disk. For example, the IsAlive or LooksAlive checks may fail. Therefore, the group in which that disk resides may fail over to another node in the cluster. A failover interrupts the CHKDSK command and affects the availability of all other resources during the failover.

Extended maintenance mode
Windows Server 2003 SP1 added another feature to the Cluster.exe command-line tool. The tool now waits for the internal state of a resource to stabilize and to complete the online or offline process. This process can be scripted. For example, after you put a resource in extended maintenance mode, the script calls the /waitmaint parameter. The /waitmaint parameter blocks activity until the resource has gone into a full stable state internally. Use the following command syntax to call the /waitmaint parameter:

cluster  /waitmaint[pending]

This update enables the maintenance mode process to perform the following extended functions:
 * The Cluster service gives over control at the LUN level to other applications or functions that need exclusive access to the LUN.
 * The Cluster service gives over complete control of the whole LUN to another application for a short time.
 * The Cluster service suppresses low-level periodic SCSI reservations and the writes to reserved sectors to guarantee LUN availability.
 * The Cluster service suppresses the LooksAlive and IsAlive health monitoring checks.

When you use extended maintenance mode, the disk is put into an offline functional state &quot;internally&quot;. When an internal function takes the disk offline, the LUN is dismounted, and all health monitoring is stopped. However, the disk appears to be in an online state at a higher level in Cluster Administrator. Also, the disk appears to be in an online state to dependent resources. The disk does not fail and is not taken offline. Therefore, the dependent resources remain online.

You can use extended maintenance mode together with a hardware snapshot application to perform any functions that are required to complete a snapshot restore. For example, you can mask off a LUN, swap LUNs, put a LUN in read-only mode, and so on.

Important A backup requestor application must provide the timing coordination during a snapshot restore to make sure that the correct application VSS writers are called. Application VSS writers make sure that all handles are closed and that there is no disk usage. Timing coordination prevents an adverse effect on higher level applications when the disk dismount occurs. After the snapshot restore is completed, the disk must be brought out of extended maintenance mode to make sure that the disk is mounted and ready to be accessed by applications.

When extended maintenance mode hands over complete control of the LUN to another process, such as to the operating system, the disk is dismounted. In this case, the disk is inaccessible to applications. Use extended maintenance mode only together with a backup requestor application that stops all usage of a disk by applications before the backup requestor application invokes extended maintenance mode. If disk usage is not stopped, application failures and potential corruption of data may occur. Extended maintenance mode should be started only by backup requestor applications that are configured by independent software vendors (ISVs). These ISVs must be familiar with application VSS writers and similar mechanisms that help prevent timing problems.

Warning We do not recommend that you use maintenance mode to bypass health monitoring checks for a disk that is experiencing problems. When a disk is in maintenance mode, any failures or time-outs of the disk are ignored by the Cluster service. This behavior may prevent failover and recoverability if a disk is intentionally or accidentally left permanently in maintenance mode.

How to put a disk in maintenance mode
To start maintenance mode, use one of the following methods:
 * Use the Cluster.exe command-line tool.
 * Use the Cluster API. For more information about how to use the Cluster API, see the Microsoft Windows Server 2003 SDK.

Put a disk resource in maintenance mode only if it meets all the following requirements:
 * The disk must be a &quot;Physical Disk&quot; type resource.

Note Resources that use other resource DLL types cannot be put in maintenance mode.
 * The disk must not be designated as the quorum resource.
 * The disk must be online.

When you put a disk in maintenance mode, this setting is an in-memory state and is not saved in the cluster registry hive. This change is not a persistent change. The next time that a disk is brought offline and then back online, the disk reverts to its standard behavior.

If there is any change to the state of the disk resource in maintenance mode, the maintenance mode setting is disabled. The maintenance mode setting is disabled when the following conditions are true:
 * You take a resource offline.
 * You change the resource status to Offline Pending or to Failed.

Also, if the disk fails over to another node, or another similar action occurs, the disk switches from maintenance mode to regular operational behavior and continues health monitoring. This behavior makes sure that you do not accidentally leave disks in permanent maintenance mode.

The Cluster.exe command-line tool is used to query, to set, and to clear maintenance mode for a resource.

Note You cannot view, change, or set maintenance mode for a resource from the Cluster Administrator graphical user interface tool.

Maintenance mode command-line syntax
To put a disk resource in maintenance mode, use the following Cluster.exe command syntax:

cluster.exe. res &quot;% %&quot; /maint:on

Note For more information about Cluster.exe command syntax, type cluster /? at a command prompt.

The following is sample output that shows that a resource has been put in maintenance mode: <pre class="fixed_text"> G:\>cluster TestCluster res &quot;Disk H:&quot; /maint:on Setting maintenance mode for resource 'Disk H:' Resource            Group                Node            Status --- -- Disk H:             Exchange             Node1           Online(Maintenance) Use the following Cluster.exe command syntax to query a disk resource to determine whether the resource is in maintenance mode:

Cluster.exe. res &quot;% %&quot; /maint

The following sample output shows a resource that is being queried for its maintenance mode setting: <pre class="fixed_text"> G:\>cluster TestCluster res &quot;Disk H:&quot; /maint Resource            Group                Node            Status --- -- Disk H:             Exchange             Node1           Online(Maintenance) Use the following Cluster.exe command syntax to bring a disk resource out of maintenance mode:

cluster.exe. res &quot;% %&quot; /maint:off

The following sample output shows a resource that is out of maintenance mode: <pre class="fixed_text"> G:\>cluster TestCluster res &quot;Disk H:&quot; /maint:off Clearing maintenance mode for resource 'Disk H:' Resource            Group                Node            Status --- -- Disk H:             Exchange             Node1           Online

How to put a disk into extended maintenance mode
<ol>  Before you put a disk in extended maintenance mode, you must put the disk in maintenance mode. To do this, type cluster res &quot;Disk H:&quot; /maint:1, and then press ENTER.

Note Both the 1 value and the ON value turn on maintenance mode. In this step, 1 is used to turn on maintenance mode.

You receive the following output: <pre class="fixed_text"> Setting maintenance mode for resource 'Disk H:' Resource            Group                Node            Status --- -- Disk H:             Exchange             Node1           Online(Maintenance) </li>  Put the disk in extended maintenance mode. To do this, type cluster res &quot;Disk H:&quot; /extmaint:1, and then press ENTER.

You receive the following output: <pre class="fixed_text"> Setting extended maintenance mode for resource 'Disk H:' System error 997 has occurred (0x000003e5). Overlapped I/O operation is in progress. Note Error 997 is expected because the return status of the Cluster.exe program is not dynamic. Therefore, it may take several seconds to put the disk in extended maintenance mode. </li>  Type cluster res &quot;Disk H:&quot;, and then press ENTER.

You receive the following output: <pre class="fixed_text"> Listing status for resource 'Disk H:': Resource            Group                Node            Status --- -- Disk H:             Exchange             Node1           Online(Ext Maintenance, Internal State 'Offline') </li></ol>

How to bring a disk out of extended maintenance mode
<ol>  Type cluster res &quot;Disk H:&quot; /extmaint:0, and then press ENTER.

You receive the following output: <pre class="fixed_text"> Clearing extended maintenance mode for resource 'Disk H:' System error 997 has occurred (0x000003e5). Overlapped I/O operation is in progress. </li>  Type cluster res &quot;Disk H:&quot;, and then press ENTER.

You receive the following output: <pre class="fixed_text"> Listing status for resource 'Disk H:': Resource            Group                Node            Status --- -- Disk H:             Exchange             Node1           Online(Maintenance) The disk is now in maintenance mode. </li>  Bring the disk out of maintenance mode. To do this, type cluster res &quot;Disk H:&quot; /maint:0, and then press ENTER.

You receive the following output: <pre class="fixed_text"> C:\WINDOWS\Cluster> Clearing maintenance mode for resource 'Disk H:' Resource            Group                Node            Status --- -- Disk H:           Exchange            Node1          Online </li></ol>

Extended maintenance mode limitations
A backup and restore application must be able to &quot;hot swap&quot; a cluster disk without taking the disk offline. Hot swapping occurs when you remove a device from a computer that is running and then replace that device with an identical device in the same slot. When a cluster disk is online, the Clusdisk.sys driver is attached to the disk and helps protect the disk. When a disk is removed from the system, all state Clusdisk.sys and disk resource maintain operations for an online disk are invalidated. The hot swap disk has to be brought online by the Clusdisk.sys driver and by disk resource operations before the hot swap disk can be used by the applications. You must perform all the operations that are described in this article without taking the corresponding cluster resource for the disk offline.

To support hot swapping, cluster disk resource operations must be able to bring the disk offline and online internally. For example, the LUN must be dismounted, and all monitoring must stop. However, the corresponding cluster resource must remain online. When hot swapping is completed, the LUN is remounted, and monitoring resumes.

When you put a disk in extended maintenance mode, the state transitions are symmetric. When a disk is online, you can switch to maintenance mode. From maintenance mode, you can switch to extended maintenance mode. However, when a disk is online, you cannot switch directly to extended maintenance mode.

A regression has been found in this update that prevents you from creating a quorum by using Majority Node Set (MNS). If you convert from shared quorum resource to MNS, an error 1 (invalid function) occurs. If the Cluster is already using MNS for a quorum and you apply this update, the MNS resource cannot come online. Additionally, Cluster administrator displays the following error message:

An error has occurred attempting to make <MNS_Resource> the quorum resource. Incorrect function

Error ID: 1 (00000001). Snippit from the cluster log:

Majority Node Set <MNS>: Expanded path '\\fa67fd8c-7325-4\fa67fd8c-7325-4751-bf3b-d3f3131f32b6$' [FM]

FmSetQuorumResource: Entry, pszClusFileRootPath=\\fa67fd8c-7325-4\fa67fd8c-7325-4751-bf3b-d3f3131f32b6$\MSCS 000000ac.00001038::2006/10/01-03:38:13.370 ERR [FM] FmSetQuorumResource: Unable to get maintenance mode info for resource 'MNS', status 1 [FM]

FmSetQuorumResource: Exit, status=1 [FM]

FmSetQuorumResource: Entry, pszClusFileRootPath=\\fa67fd8c-7325-4\fa67fd8c-7325-4751-bf3b-d3f3131f32b6$\MSCS 000000ac.00001758::2006/10/01-03:38:59.730 ERR [FM] FmSetQuorumResource: Unable to get maintenance mode info for resource 'MNS', status 1 [FM] FmSetQuorumResource: Exit, status=1

To resolve the issue with MNS, please download the following update: An update is available that adds a file share witness feature and a configurable cluster heartbeats feature to Windows Server 2003 Service Pack 1-based server clusters http://support.microsoft.com/kb/921181/en-us

Service pack information
To resolve this problem, obtain the latest service pack for Windows Server 2003. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

889100 How to obtain the latest service pack for Windows Server 2003

Restart requirement
You must restart the computer after you apply this update.

Update replacement information
This update does not replace any other updates.

File information
The English version of this update has the file attributes (or later file attributes) 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 item in Control Panel.

Windows Server 2003, x86-based versions
<pre class="fixed_text"> Date        Time   Version            Size    File name --  18-Aug-2005  04:54  5.2.3790.2511     476,672  Clusres.dll 18-Aug-2005 02:39  5.2.3790.2511     838,144  Clussvc.exe 18-Aug-2005 02:40  5.2.3790.2511     181,248  Cluster.exe 18-Aug-2005 02:40  5.2.3790.2511      68,096  Resrcmon.exe 18-Aug-2005 02:33  5.2.3790.2511       7,168  W03a2409.dll 18-Aug-2005 02:48  5.2.3790.2511      32,256  Arpidfix.exe

Windows Server 2003, x64-based versions
<pre class="fixed_text"> Date        Time   Version            Size    File name    Platform 18-Aug-2005 14:19  5.2.3790.2511     651,264  Clusres.dll      x64 18-Aug-2005 14:19  5.2.3790.2511   1,231,360  Clussvc.exe      x64 18-Aug-2005 14:19  5.2.3790.2511     338,432  Cluster.exe      x64 18-Aug-2005 14:19  5.2.3790.2511      97,280  Resrcmon.exe     x64 18-Aug-2005 14:19  5.2.3790.2511       7,680  W03a2409.dll     x64 18-Aug-2005 14:19  5.2.3790.2511     181,248  Wcluster.exe     x86 18-Aug-2005 14:19  5.2.3790.2511      68,096  Wresrcmon.exe    x86 18-Aug-2005 14:19  5.2.3790.2511       7,168  Ww03a2409.dll    x86 18-Aug-2005 14:19  5.2.3790.2511      43,008  Arpidfix.exe     x64

Windows Server 2003, Itanium-based versions
<pre class="fixed_text"> Date        Time   Version            Size    File name    Platform 18-Aug-2005 14:19  5.2.3790.2511   1,162,240  Clusres.dll      IA-64 18-Aug-2005 14:19  5.2.3790.2511   2,068,992  Clussvc.exe      IA-64 18-Aug-2005 14:19  5.2.3790.2511     543,744  Cluster.exe      IA-64 18-Aug-2005 14:19  5.2.3790.2511     184,320  Resrcmon.exe     IA-64 18-Aug-2005 14:19  5.2.3790.2511       6,144  W03a2409.dll     IA-64 18-Aug-2005 14:19  5.2.3790.2511     181,248  Wcluster.exe     x86 18-Aug-2005 14:19  5.2.3790.2511      68,096  Wresrcmon.exe    x86 18-Aug-2005 14:19  5.2.3790.2511       7,168  Ww03a2409.dll    x86 18-Aug-2005 14:19  5.2.3790.2511      74,752  Arpidfix.exe     IA-64

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

824684 Description of the standard terminology that is used to describe Microsoft software updates

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STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section. This problem was first corrected in Windows Server 2003 Service Pack 2.

Keywords: kbwinserv2003sp2fix kbhotfixserver kbqfe KB903650

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