ENA has been validated against Neverfail Heartbeat 5.5.2153 and Neverfail 6 from Artisan Infrastructure on Windows platforms, requiring no additional adapter.
Please consult the Neverfail documentation and your Entuity representative before installing ENA as part of a High Availability solution.
Overview of the Neverfail configuration:
With Neverfail, high availability of the Entuity server is maintained during a service failure by transferring the Entuity server identity from the primary server to the backup server. The Entuity server identity includes its host identifier, IP address, hostname and all of its registry settings.
Neverfail needs to be installed to 2 servers:
- on the primary (active) server, ENA runs and manages the network.
- on the backup (passive) server, Neverfail maintains a copy of the primary server's ENA install, regularly updating the secondary install with changes in the primary's dynamic data, e.g. reports, database, log files.
Neverfail maintains high availability of the Entuity server during a service failure by transferring the Entuity server identity from the primary servere to the backup server. The Entuity server identity includes its IP address, hostname and all registry settings.
Post transfer, ENA is unaware that it is now running on a different machine. Neverfail also ensures that only one server (initially the primary server and then the backup server) is visible to the network at any one time.
Checking ENA licenses:
For each server that may potentially need to run ENA, you must have an ENA license locally installed to that machine. ENA licenses are not transferable between servers. For your ENA supplier to generate a valid license, you must provide the host identifier.
To configure Neverfail to deliver High Availability:
- The primary and secondary servers should have the same hardware specification. Run a scope report on both machines as part of your pre-installation process.
- Set up ENA with a static IP address, which is not assigned from a DHCP server.
- Ensure the DNS configuration can fully convert this static IP address to a fully qualified name.
- Neverfail should be installed to its primary and backup servers. Configure Neverfail to exclude the ENA license file from the duplication process.
- A third IP address, the Management Client Connection Point, is for the active server to receive pings from the passive server. When Neverfail does not receive a response to the ping, Entuity is considered down.
- Install ENA to the primary server, including its license file.
- Through Neverfail, an exact copy of the ENA install that is on the primary server is then made to the backup server.
- Install the backup server’s ENA license.
- Run ENA on the primary server.
- Neverfail intercepts every disk I/O requests and sends it to the backup server, where it is also written to the backup server’s hard disk.
- If the primary server goes down, Neverfail on the backup server detects this failure and will do the following:
- start ENA on the backup server. ENA's startup process detects that the database on the primary server did not shutdown properly and initiates the database repair process. The larger the database, the longer it will take to complete the process during which time ENA cannot poll for data.
- ensure that the IP address and DNS resolution is swapped to the backup server. This switch is transparent to the user, with the only sign being a short outage period.
- After the installation has been replicated, the file system filters should be set to only replicate dynamic data:
- entuity_home\log\mysqld.error.log (this may be configured to be somewhere other than under entuity_home)
- The mysqld.error.log file requires replication as it is checked by dbcheck at ENA startup to determine the state of the database server when it was last shut down.