Deploying Neverfail Continuity Engine
Welcome to the Neverfail Continuity Engine e-learning session! This session introduces you to additional considerations when deploying Neverfail Continuity Engine in a production environment.
Neverfail Continuity Engine is implemented using a simple multi-step procedure that installs the Neverfail Continuity Engine Management Service and then deploys the Neverfail Continuity Engine servers. To ensure that your implementation is successful, you should address these considerations before and during the installation process. So let's get started!
Learning objectives
Upon completion of this e-learning session you should be able to:
- Identify prerequisites to application protection, recall how the Neverfail Continuity Engine cloning process affects or makes use of the following: machine name, security ID or SID, Windows filtering platform and the IP address in LAN environments.
- Recall how cached logging credentials are used on passive servers
- Recall Neverfail Continuity Engines effect on protected application services
- Identify how Neverfail Continuity Engine makes use of Windows plug-and-play during the installation process
- Recall the conceptual process of stretching from a LAN based installation to a WAN based installation.
Considerations for installation
While other sessions discussed the Neverfail Continuity Engine software installation process, this session addresses considerations for installation and implementation of the product. Read below to find out more.
Immediately after successfully deploying Neverfail Continuity Engine, it is important to remember that Neverfail Continuity Engine provides limited protection and does not allow a managed or automatic switchover until the initial synchronization is complete. In other words, Neverfail Continuity Engine permits switchovers only if the servers are synchronized. The initial synchronization takes place immediately after installation. However, this rule does not apply to failovers for missed heartbeats. Neverfail Continuity Engine will allow an automatic failover to a passive server at all times, regardless of the synchronization state of the server.
Because of the cloning process used during deployment, the secondary and tertiary, if installed, servers are identical to the primary server, including the primary’s machine name, security ID, program files and application services. In a LAN environment IP addresses are duplicated between servers, whereas in a WAN environment the service will normally be in different subnets and consequently will have different IP addresses.
Since the primary, secondary and, if it's installed, tertiary servers are clones of one another, all incorporate the Windows filtering platform to prevent IP address and machine name conflicts. The servers functioning in the passive role are blocked from the corporate network, while the Neverfail Channel Network connections are not filtered. This configuration allows replication data and heartbeat signals to be communicated to the other servers in the Neverfail Continuity Engine cluster. Neverfail Continuity Engine manages the state of the filter, either passing or blocking packets.
Passive server login
Since the passive servers are blocked from the corporate network, they can no longer authenticate against the domain controller. Instead, they use cached credentials for login. You must enable the use of cached credentials to be able to login with domain accounts.
Note: logins will take longer on the passive servers because the passive servers will attempt to contact the main controller and will use cached credentials after the attempted connection to the domain controller has timed out.
Additional installation considerations
During installation, Neverfail Continuity Engine performs multiple tasks to prepare the servers for Neverfail operations. Read below to find out more.
Physical to virtual
Neverfail Continuity Engine incorporates VMware's vCenter Converter to create a virtual clone of a physical primary server, as part of the Neverfail Engine deployment process. It includes the following: documents and settings folder, Neverfail folder, program files folder, the protected applications data set, program files for applications protected by Neverfail application plugins which are not installed to the program files folder, Windows folder and system state.
Services set to manual
For successful replication of data to the passive servers, the protected applications cannot be running on these servers when they are passive. Otherwise, those applications will lock their data files and consequently block Neverfail Continuity Engine’s replication process. Therefore, as part of the installation process, Neverfail Continuity Engine sets all services related to any protected applications to start up manually. Neverfail Continuity Engine will start these services on the active server during the start up process. As long as Neverfail Continuity Engine is installed, services should not be reverted to start up automatically. The Neverfail Continuity Engine program sets the services back to automatic if you should uninstall the product.
Plug-and-play or PnP
Following the deployment process of the secondary and tertiary server, if installed, Neverfail Continuity Engine uses the Windows plug-and-play process to address any differences in machine hardware, between the primary, secondary and tertiary servers. Where hardware is identical, such as with two virtual machines, for example, plug-and-play may not run. During the plug-and-play process you may need to reinstall device drivers on the secondary and tertiary servers manually. Ensure that all device drivers are readily available should Windows require them. Following the deployment process, most all of the secondary and, if installed, tertiary server's settings are identical to the primary server. Take the opportunity to verify that the public and channel network settings are properly configured for each server.
LAN to WAN
Neverfail Continuity Engine’s ability to move from a LAN environment to a WAN environment allows organizational flexibility and increased disaster recovery capabilities.
The process is simple and can be accomplished post implementation. Neverfail strongly recommends that you perform WAN implementations initially in a LAN environment, so that you can conduct data transfer and testing in the most controlled convenient manner.
After Neverfail Continuity Engine is up and running in a LAN environment, the secondary or tertiary server can be moved off-site to a WAN location. Neverfail also recommends that you run SCOPE to measure available bandwidth to the proposed new location, to ensure that sufficient capacity is available.
Moving from a LAN to a WAN configuration introduces the need to reconfigure some aspects of the Neverfail Continuity Engine software. Most notably, the server will be part of a different subnet, requiring changes to the corporate and channel network configurations.
Additional start up tasks must be added to ensure DNS updates occur during the switchover process, directing clients to the new active server’s IP address. You are advised to enable the WAN acceleration feature and also adjust automatic fail over properties, adjust network monitoring configuration and enable split-brain avoidance.
You can find step-by-step instructions on how to complete a LAN to WAN stretch in the Neverfail Extranet knowledge base.
Summary
Remember these additional considerations when installing Neverfail Continuity Engine.
- Neverfail Continuity Engine servers must synchronize before switchover capabilities become available.
- The cloning process replaces all configuration settings to the secondary and, if installed, the tertiary servers, including machine name, SID, program files, Windows services and, in a LAN environment, the IP addresses.
- Neverfail Continuity Engine implements Windows filtering platform to prevent IP and machine name conflicts on the corporate network.
- Passive servers use cached credentials for logging into domain accounts.
- To enable replication, Neverfail Continuity Engine sets all the services for protected applications to start up manually.
- Windows plug-and-play addresses differences between the primary secondary and tertiary servers hardware.
- With minor reconfiguration, Neverfail Continuity Engine can stretch from LAN to WAN easily to accommodate the needs of an organization.
This knowledge, combined with knowledge gained from other Neverfail sessions, will assist you in achieving success with your Neverfail Continuity Engine product.
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