Neverfail Heartbeat Synchronization Failures (V5.2.2 and Earlier)



This Knowledgebase article provides information about how to resolve Neverfail synchronization failures including the symptoms, causes, and resolutions.

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When Neverfail Heartbeat is started, a Full System Check occurs. This ensures that:

  • All protected File/Folder structure from the active server is present on the passive server
  • All protected Registry Keys and values from the active server are present on the passive server

After the Full System Check finishes, the File System Status and the Registry Status should both be shown as Synchronized . However, there may be cases when the File System Status or the Registry Status are shown as Out of sync or Synchronized and busy processing . Some of the cases are described below, with possible reasons and workarounds.

Services Running on the Passive Server


File System Status is Out of sync or Synchronized and busy processing .


A service that is running on the passive server may open a protected file for exclusive access. If Neverfail Heartbeat attempts to update a file, which has been opened in this way, the following error is logged by the Apply component:

[N29]The passive Neverfail server attempted to access the file: {filename}. This failed because the file was in use by another application. Please ensure that there are no applications which access protected files running on the passive.

Services that keep files locked on the passive server might be:

  • Protected application services.
  • File-level anti-virus tool services.
  • The NNTP service in a Neverfail for IIS deployment (if the \Inetpub folder is shown as Out of sync )
  • IISAdmin service in a Neverfail for IIS deployment (if the C:\WINDOWS\system32\inetsrv\Metabse.xml is shown as out of sync). IISAdmin service starts on the passive after a reboot of the server. It needs to be manually stopped.
  • Print Spooler service (if C:\WINDOWS\system32\spool\drivers is shown as out of sync)
  • MSDTC service (if C:\WINDOWS\system32\MsDtc\MSDTC.LOG is shown as out of sync)


Until the file is closed on the passive server, Neverfail will report that file's status, and hence the File System Status, as Out of sync .

To resolve an Out of Sync system status, take the actions below:

  • Ensure Protected Application services are set to Manual on both servers and that they are not running on the passive server.
  • Ensure that the Neverfail Application Module Monitor service is set on Manual on both servers and it is not running on the passive server (otherwise, this service will restart the Protected Application services when finding them stopped).
  • Ensure that the Recovery Actions set from the Service Control Manager(SCM) for the Protected Application services are Take No Action (otherwise, the Protected Application services will be restarted by the SCM)
  • Ensure that file-level anti-virus is not part of the protected set as the file-level anti-virus and the corresponding services are running on both machines.
  • Ensure the NNTP service is not running on the passive server in a Neverfail for IIS deployment (if the \Inetpub folder is shown as Out of sync ). This is valid for some of the Exchange implementations as well, where IIS Admin is protected.
  • Ensure that IISAdmin is not running on the passive server in a Neverfail for IIS deployment (if the file C:\WINDOWS\system32\inetsrv\MetaBase.xml is out of sync).
  • Ensure that C:\WINDOWS\system32\spool\drivers is not part of the file filters set. See Knowledgebase Article #1208 Does Neverfail Heartbeat protect Print Servers? for Neverfail recommendations regarding Print Servers.

Neverfail Channel Incorrectly Configured


If the Neverfail Channel is not properly configured, it cannot initiate the handshake which establishes communications through the channel connection. Failure to establish the channel connection will prevent a Full System Check thereby leaving the File System Status and Registry Status as Out of Sync .


The most common Neverfail channel configuration errors are:

  • Neverfail packet filter enabled on one or more channel NICs
  • Channel IP addresses configured in different subnets
  • In a WAN implementation, no static routes between the channel NICs


To resolve a Neverfail Channel configuration error:

  • Verify that the Neverfail packet filter is disabled on channel NICs
  • Verify that channel IP addresses are properly configured
  • In a WAN implementation, verify that static routes between channel NICs are properly configured
  • Ensure that NetBIOS settings on the channel NICs have been disabled

Incorrect or Mismatched Disk Configuration

Common disk configuration errors which may affect a Neverfail Heartbeat server pair:


When Neverfail Heartbeat starts, the complete set of File Filters is checked for consistency. If any of the entries points to a non-existant drive letter or to a non-NTFS partition, the list of File Filters will be reset to the default value of C:\Protected\**. This is a safety measure; Neverfail Heartbeat requires the same drive letter configuration on the Primary and the Secondary servers, and only supports protection of NTFS partitions.


Different partition structures on Primary and Secondary servers, such that one or more file filters point to drives which cannot be protected on both servers. For example:

  • The Primary server has drive G:, which is a valid NTFS partition; but there is no corresponding drive on the Secondary server
  • The Primary server has drive G:, which is a valid NTFS partition; but the equivalent drive on the Secondary server is a CD / DVD drive or a FAT / FAT32 partition, which cannot be protected by Neverfail Heartbeat.

In either case, if a file filter is configured to protect a directory on drive G:, the entire filter set will be rejected and the filters will be reset to the default value of <Windows drive>\Protected\**.


If this occurs, you should follow the steps documented in Knowledgebase Article #500 - The Set of File Filters is Reset to C:\Protected\**. What Should I Do Next? .

The Passive Server Has Less Available Space than the Active Server


Replication will stop and the following error is reported:

[N27]Failed to write information for the file: {filename} to the disk. Either the disk is full or the quota (for the SYSTEM account) has been exceeded.


The passive server has less available disk space than the active server, preventing updates from being replicated to the passive server, because the quantity of updates from the active server exceed the passive server's available disk space.


Free up some additional disk space on the passive server. Make sure you are not deleting data from the protected set as you might lose data in the event of a switchover. You may need to update the disk subsystem on the passive server. Once complete, you will need to start replication.

Unprotected File System Features


Another possible reason why Neverfail Heartbeat cannot synchronize certain files or directories is the presence in the replication set of so-called unprotected file system features.

The default behavior for Heartbeat in the presence of Unprotected Features from category 2 (Extended Attributes and file encryption) is to log an error and set the File System Status to Out Of Sync . If these types of files are present in the replication set, replication continues, but the system will remain Out of Sync .


Neverfail will not synchronize if the replication set contains files with unprotected file system features. Unprotected file system features are described by category in Knowledgebase Article #321 Neverfail for File Server: Unprotected Features of the Windows 2000 / 2003 File System


Two methods of dealing with these Unprotected Features are described in Knowledgebase Article #321 Neverfail for File Server: Unprotected Features of the Windows 2000 / 2003 File System . If these features are not essential for the normal operation of your file system, zipping and unzipping the affected files within their parent directory should remove the Unprotected Features, allowing the Neverfail Heartbeat to synchronize the file system.

Registry Status is Out of Sync

The Registry may be reported as Out Of Sync when one or more Registry keys fail to synchronize. There are at least two possible reasons.

Resource Issues


Neverfail Heartbeat logs the following error message:

Call to RegOpenKeyEx failed: on <Reg_Key> : Insufficient system resources exist to complete the requested service


One or both of the servers are running low on virtual memory.


This is usually a sign that the server does not have enough virtual memory left. A restart of the server should correct this problem.

Registry security issues


Neverfail is unable to read/sync/replicate the registry.


If a protected registry key has permissions that deny Write access to the System account, Neverfail Heartbeat may be unable to synchronize or replicate it.


Change the permissions on the affected registry key to grant the System account Full Control .

NOTE: Some antivirus solutions prevent any writes at the registry level, so even if Neverfail Heartbeat has the required permissions it cannot synchronize the registry.

Applies To

Neverfail Heartbeat V5.2.2 and Earlier

Related Information

Knowledgebase Article #1433 Neverfail Heartbeat Synchronization Failures (V5.3.0 and More Recent)


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