EVault - Synchronization Failures

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Summary

This Knowledge Base article provides information about how to resolve EVault Remote Disaster Recovery synchronization failures including the symptoms, causes, and resolutions.


More Information

When EVault Remote Disaster Recovery is started, a Full System Check occurs. This ensures that:

  • All protected File/Folder structures from the active server are 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 and the Registry Status should both be shown as Synchronized . However, there may be cases when the File System or the Registry Status is 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

Symptoms

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

Cause

A service that is running on the passive server may open a protected file for exclusive access. If EVault Remote Disaster Recovery attempts to update a file that was opened in this way, the following error is logged by the Apply component:

[N29]The passive EVault Remote Disaster Recovery 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 server.

Services that keep files locked on the passive server include:

  • Protected application services
  • File-level anti-virus tool services
  • The NNTP service in a EVault Remote Disaster Recovery IIS deployment (if the \Inetpub folder is shown as Out-of-Sync )
  • IISAdmin service in a EVault Remote Disaster Recovery IIS deployment (if the C:\WINDOWS\system32\inetsrv\Metabse.xml is shown as Out-of-Sync ). IISAdmin service starts on the passive server after a reboot of the server and must be stopped manually.
  • 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 )

Resolution

Until the file is closed on the passive server, EVault Remote Disaster Recovery reports the file 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 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 antivirus is not part of the protected set as the file-level antivirus and the corresponding services are running on both machines. See RDR-REFID-104 EVault Remote Disaster Recovery and Anti-Virus Tools - General Advice Regarding Interoperability with Anti-Virus Scanners .
  • Ensure the NNTP service is not running on the passive server in aEVault Remote Disaster Recovery IIS deployment (if the \Inetpub folder is shown as Out-of-Sync ).
  • Ensure that IISAdmin is not running on the passive server in a EVault Remote Disaster Recovery 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.

EVault Channel Incorrectly Configured

Symptoms

If the EVault 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 .

Cause

The most common EVault Channel configuration errors are:

  • EVault Remote Disaster Recovery Packet Filter enabled on one or more EVault Channel NICs
  • Channel IP addresses configured in different subnets
  • In a WAN implementation, no static routes between the channel NICs

Resolutions

To resolve a EVault Channel configuration error:

  • Verify that the EVault Remote Disaster Recovery Packet Filter is disabled on EVault 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

The Passive Server has Less Available Space than the Active Server

Symptoms

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.

Cause

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.

Resolution

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

Symptoms

Another possible reason why EVault Remote Disaster Recovery cannot synchronize certain files or directories is the presence in the replication set of so-called "unprotected" file system features.

The default behavior for EVault Remote Disaster Recovery 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 .

Cause

EVault Remote Disaster Recovery will not synchronize if the replication set contains files with unprotected file system features. Unprotected file system features are described by category in RDR-REFID-321 Unprotected Features of the Windows 2003 File System

Resolution

Two methods of dealing with these Unprotected Features are described in RDR-REFID-321 Unprotected Features of the Windows 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 EVault Remote Disaster Recovery to synchronize the file system.

Registry Status is Out-of-Sync

If one or more Registry keys fail to synchronize, the Registry may be reported as Out-of-Sync . There are at least two possible reasons for this, resource issues and registry security issues.

Resource Issues

Symptoms

EVault Remote Disaster Recovery logs the following error message:

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

Causes

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

Resolutions

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

Registry Security Issues

Symptoms

EVault Remote Disaster Recovery is unable to read/sync/replicate the registry.

Causes

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

Resolutions

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 EVault Remote Disaster Recovery has the required permissions it cannot synchronize the registry.


Applies To

EVault Remote Disaster Recovery All Versions


Related Information

RDR-REFID-1433

KBID-2338

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