How to Apply Windows (OS) Patches or Hotfixes on a Neverfail Continuity Engine Pair With Minimal Interruption
Summary
This article can be used to apply Windows (OS) patches or hotfixes on a Neverfail Engine pair with minimal interruption.
More Information
Neverfail Engine's unique architecture allows you to install updates of the operating system or apply hotfixes without interrupting end-users. The active/passive server group allows you to install the update or hotfix on one server and ensure functionality before installing it on the other server. Please see the instructions below on how to install an update or hotfix.
Note: If your configuration consists of Neverfail Engine in a Tertiary configuration, please see Knowledgebase article #2438 - How To Apply Operating System (OS) Patches or Hotfixes on a Neverfail Continuity Engine Trio With Minimal Interruption
Procedure
Note: The procedure assumes that Neverfail Engine is configured with the Primary server as Active and both the File System Status and Registry Status are synchronised.
Before implementing this procedure, please make sure that the Windows Automatic Update feature is configured so that Updates are NOT applied automatically. It is acceptable to allow the updates to be downloaded automatically but not installed unless first confirmed by the user.
Important:
If you have Microsoft products protected by Continuity Engine (i.e. SQL Server, Exchange, IIS Server, etc.) do not allow them to be updated automatically by Windows Update, while Engine is replicating: the risk is to have configuration changes replicated while actual binaries are not. And this may cause application inconsistency on the standby passive servers. (Engine doesn't replicate application binaries; it replicates only app config and data). Thus, do not check Give me updates for other Microsoft products when I update Windows.
Patching a Neverfail Engine pair without Management IP addresses
1. On the Primary (Active) server, launch Windows Update.2. Download and install the patches or hotfixes, but DO NOT reboot the server if instructed to do so.3. Launch the Neverfail Advanced Management Client.4. Perform a switchover using the MakeActive button in the Neverfail Advanced Management Client in order to make the Secondary server active.
Note: At this point users may notice a slight interruption to the protected application.5. Once switchover has completed, shutdown Neverfail Engine by selecting the option ' Shutdown Group, but Leave protected applications running'.6. Reboot the Primary server, if prompted at step 2, to complete the installation of the OS patches or hotfixes.7. Verify all patches and hotfixes are installed properly on the Primary server.8. Start Neverfail Engine service on both Primary and Secondary servers, if no reboot was required at step 6.9. Allow servers to connect and synchronize with the Secondary as Active and the Primary as Passive.10. Once synchronisation has completed, launch the Windows Update on the Secondary (Active) server.11. Download and install the patches or hotfixes, but DO NOT reboot the server if instructed to do so.12. Launch the Neverfail Advanced Management Client.13. Perform a switchover using the MakeActive button in the Neverfail Advanced Management Client to make the Primary server Active again (just like you did at step 4).
Note: At this point users may notice a slight interruption to the protected application.14. Once switchover has completed, shutdown Neverfail Engine by selecting the option 'Shutdown Neverfail Engine, but Leave protected applications running'.15. Reboot the Secondary server, if prompted so at step 11, to complete the install of the OS patches or hotfixes.16. Verify all patches are installed properly on the Secondary server.17. Start Neverfail Engine service on both Primary and Secondary servers, if no other reboot was required at step 15.18. Allow servers to connect and synchronise with the Primary as Active and the Secondary as Passive.19. On the Primary (Active) server, launch Windows Update again and check for any further updates that may be required. If additional updates are required, repeat steps 2 to 18.
Applies To
Neverfail Continuity Engine
Related Information
None
KBID-2848
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