Summary

This Knowledgebase article provides information about this specific release of the Neverfail System Plug-in designed to provide system performance monitoring capabilities for Neverfail Continuity Engine servers.

What's New

• Split-Brain Avoidance (SPA) auto-configuration: the new System plugin brings by default a periodic task which executes once per day and configures automatically SPA ping routing definition if the Continuity Engine management IP addresses are defined for Primary and Secondary (at least one IP address for each node).  Continuity Engine management IP addresses are defined using the Configure Server wizard. Split-brain avoidance ping routes can be configured only between Continuity Engine management IP addresses. 
  
• What do I need to do to activate this safety-net? Just define at least one management IP address on each Primary and Secondary node.
  
• Default inclusion file filter %ProgramData%\Neverfail-Protected\** -  this is installed and enabled by default at install or upgrade by this updated plugin. This protected location is recommended to be used as a container for all the user-defined auxiliary scripts, files, etc. required to be replicated, thus present, on all Continuity Engine nodes. 

Fixes

1. [EN-5981]: Scope Data Collector Service protection is not disabled correctly when configured not to protect the diagnostic service (from plugin configuration wizard).

About Neverfail System Plug-in

The Neverfail System Plug-in for Neverfail Continuity Engine adds system performance monitoring features to identify critical hardware and operating system performance issues that could affect system availability.

Supported Versions of Microsoft Windows

x64 / Intel 64 Platform (64-bit hardware)

• Microsoft Windows Server 2022 Standard / Datacenter
• Microsoft Windows Server 2019 Standard / Datacenter
• Microsoft Windows Server 2016 Standard / Datacenter
• Microsoft Windows Server 2012 R2 Standard / Datacenter
• Microsoft Windows Server 2012 Standard / Datacenter
• Microsoft Windows Server 2008 R2 Standard / Enterprise / Datacenter

Monitoring

Monitoring the system environment can be broadly categorized as:

• Active Server and Service Availability Monitoring
  
• Split-Brain Avoidance Configuration Monitoring
• Application and Performance Monitoring

Active Server and Service Availability Monitoring

Neverfail Continuity Engine monitors the availability of a server by sending continuous heartbeat signals via the Neverfail Channel to the other server in the pair. The “Yes I am alive” response ensures that not only is the other server powered-up, but also that it is available if needed. The heartbeat signal interval is configurable from the Advanced Management Client.

Split-Brain Avoidance Configuration Monitoring

Neverfail Continuity Engine monitors the management identity configuration and will automatically configure a set of ping routes which will be used to avoid potential split-brain situations when failover is initiated as a consequence of channel loss. The automatic configuration of split-brain avoidance requires a minimum of one management IP address defined on each Primary and Secondary nodes.  Split-brain avoidance works by pinging from the passive server to the active server across the client network. If the active server responds, the passive does not failover, even if the channel connection is lost. Ping routing configuration means defining ping routes between Primary and Secondary instances using existing/defined management IP addresses.

Application and Performance Monitoring

Neverfail monitors general system performance via the Neverfail System Plug-in. The Neverfail System Plug-in performs this operation by checking select WMI counters at predetermined intervals to ensure that results of the check are within defined parameters. Neverfail System Plug-in uses 'Rules' to take action should a check reveal results outside of the defined parameters.

Note: Many of the rules listed below are provided in the disabled state because default values cannot be provided as these values depend upon the server and application load.

Protected Services

The following Services are protected by the Neverfail System Plug-in:

• DHCP Client
• SCOPE Data Collector Service  - if “Protect Diagnostic Service" option is enabled in the Edit plugin section (default is enabled)
• Task Scheduler – if “Protect Task Scheduler” option is enabled in the Edit plugin section (default is disabled)

Protected Data

Registry data, application and configuration file filters are automatically configured by the plug-in's automatic filter discovery mechanism. This will assure synchronized data between active and passive Continuity Engine nodes (live replication). 

Tasks

The following 'Tasks' are installed by Neverfail System Plug-in:

• File Filter Discovery
• Registry Filter Discovery
• Protected Services Discovery
• Application Data Discovery
  
• SplitBrainAvoidanceConfiguration (new in v401.0.7)
• Pre Stop

To configure/modify these 'Tasks', follow the steps below:

1. Using the EMS Web UI or  Advanced Management Client, click on Tasks.
2. Select the desired 'Task'.
3. Click on the Edit button at the top of the 'Tasks' pane.
4. Configure/modify the 'Interval' field. 
   Note: 'Interval' is the only field available for configuration/modification and is measured in seconds (secs).
5. Click OK to save the changes.
   Note: This dialog is also used to Enable/Disable the selected 'Task'.

Rules

The following Performance Monitoring Rules are installed by the Neverfail System Plug-in:

• Disk Avg Secs Per Read
• Disk Avg Secs Per Write
• Disk IO
• Disk Queue Length
• Disk Reads Per Sec
• Disk Writes Per Sec
• Disk Writeable
• Free Disk Space
• Free Disk Space On Drive
• Memory Committed Bytes
• Memory Committed Bytes Percent
• Memory Free PTEs
• Memory Page Reads Per Sec
• Memory Page Writes Per Sec
• Memory Pages Per Sec
• Memory Paging File Usage
• Page Faults Per Sec
• Processor Ints Per Sec
• Processor Load
• Processor Queue Length
• Redirector Bytes Total Per Sec
• Redirector Network Errors Per Sec
• Server Bytes Total Per Sec
• Server Work Item Shortages >= 3 
  If the rule for server work item shortages is triggered, consult Microsoft documentation on setting the registry values for InitWorkItems or MaxWorkItems accordingly.
• Server Work Queue Length
• System Context Switches
• Version Check For Windows OS
  
• Check website availability (new in v401.0.6)

To configure/modify the Rules:

1. Launch the EMS Web UI (or Advanced Management Client).
2. Navigate to Rules.
3. Select the Rule to configure or modify from the list of Rules.
4. Click Edit... near the top of the Rules pane. The Edit Rule dialog appears.
5. Configure or modify the following fields:
   
1. Condition: (the condition being evaluated)
   
2. Duration: (the length of time the condition exists)
   
3. First Failure: (action to take upon first failure) The default is set to Alert.
   
4. Second Failure: (action to take upon second failure) The default is set to Alert.
   
5. Third Failure: (action to take upon third failure) The default is set to Alert.
   
6. Click OK to save your changes.
   

Note: This dialog also can be used to enable and disable the selected Rule.

Install and Uninstall the Neverfail System Plug-in Using the Advanced Management Client

The Neverfail System Plug-in can be installed either via the Neverfail Continuity Engine deployment process or by using Application -> Plugins in the Advanced Management Client using the procedure below. Neverfail recommends that for initial deployments of Neverfail System Plug-in, installation should be performed using Engine Management Service. 

Note: Plug-ins should be installed only on the active server. Installation of a plug-in on a passive server may cause an Exception to occur.

Install the Neverfail System Plug-in

1. Unzip the Neverfail System Plug-in to a convenient location.
2. Launch the Advanced Management Client.
3. Navigate to Applications : Plugins.
4. Click  Install... The Install Plugin dialog appears.
5. Click Browse... and navigate to the location of the SystemNFPlugin.dll file.
6. Click OK to complete the installation.

Uninstall the Neverfail System Plug-in

1. Launch the Advanced Management Client.
2. Navigate to Applications : Plugins.
3. Select the Plug-in to uninstall from the list.
4. Click Uninstall... A confirmation message appears.
5. Click Yes.  The Plug-in is uninstalled.

When the Plug-in is uninstalled, the associated files are not removed. This is by design for future functionality.  To remove these files:

1. Copy the contents of the r2\plug-ins\<sponsor>\<version> folder to a different location such as C:\temp.
2. Delete the contents of the r2\plug-ins\<sponsor>\<version> folder.
3. To reinstall the plug-in, when prompted for the location of the plug-in files, navigate to the new folder location (C:\temp).

Note: As an alternative, reinstallation can be accomplished by using the download files from the original download location after removing the plug-in.

Applies To

Neverfail System Plug-in v401.0.7
Neverfail Continuity Engine v11.0 and later