Appendix C - Redundant Servers: Setting Up And Swapping Out; Setting Up A.i.m. Server Redundancy; Operation Of Redundancy - ADDER Infinity User Manual

APPENDIX C - Redundant servers: Setting up and swapping out

This appendix contains two main sections related to the creation and repair of A.I.M.
server installations that employ redundancy.
• Setting up A.I.M. server redundancy - below
• Swapping out an A.I.M. server - on next page

Setting up A.I.M. server redundancy

This section details the steps required to successfully configure two A.I.M. units as
primary and secondary servers.
1 First determine the password requirements for A.I.M. servers. Access the Dashboard >
Settings page and click Servers button. Set the Require Authentication option as required.
If set to No, then new servers can join the network as soon as they are plugged in. If
set to Yes, you will need to enter a Cluster Password in the field below and this must be
set on every A.I.M. server.
2 Within the main Servers tab, choose the A.I.M. unit that you wish to use as the
primary server.
3 Click for the chosen A.I.M. server to display the Configure Server page and change
the Rôle entry to primary and click Save.
4 Add the new secondary A.I.M. server to the network. This unit must have its factory
default settings in place. The new server should appear within the main Servers tab and
be identified as being Unconfigured.
5 Wait five minutes for automatic server replication to take place and the backup
database to be transferred from the primary unit. After this period, the new secondary
server should be added to the list on the main Servers tab. Its Rôle will be shown as
backup and its Status as standby.
Note: If the transfer of the backup database is interrupted and only a partial database is
transferred, then the problem will be reported within the management server page. If this
occurs, it will not be possible to log in to the backup database and the firmware version of
the backup will be reported as V. After five minutes, you should be given the options of Reboot
and Factory Reset. Choose the factory reset option in order to clear this issue.
6 You can now configure the secondary server in either of two ways:
• Click the icon to configure the server remotely from the primary server.
• Click the icon to open a restricted page in order to configure the server
directly from its own IP address. If you use this option, the configuration options are
limited to: view the logs; update/reset AIM and configure this server.

Operation of Redundancy

If the Primary server fails for any reason (for example, loss of power or a network
issue) then the secondary server will failover. This will happen automatically without
any user intervention, however it is not instantaneous. The failover time required is the
value entered in the primary timeout plus 30 seconds for the process to happen. The
AdderLink Infinity extenders will start communication with the second IP address that is
stored in their configuration and the redundant server will take control of the AdderLink
Infinities. When the redundant server is acting as the primary it is not possible to add any
new devices or change the configuration. If this is required then the backup server can be
promoted to be the primary.
When the primary server comes back online then it will resume its role as the primary.
If however the backup server has been promoted to primary, when the primary server
comes back its role will need to be factory reset back to the backup. It is not possible to
have two primary servers on the same network.
Both the primary and the backup server periodically synchronize their databases to
ensure that they are identical. If for any reason the backup server is powered down then
any changes to the system configuration will not be maintained by the backup server.
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