Configuring recording high availability
The Verba Unified Call Recorder is capable of priority-based load balancing and mid-call failover. This configuration is available for Cisco and other phone systems with SIP-based recording.
The load balancing and mid-call failover capabilities are highly dependent on the phone system!
Overview
The Verba Unified Call Recorder contains a Recording Director and a Media Recorder module. The Recording Director module handles the incoming SIP connection(s) and decides which Media Recorder should receive which call's media stream. The Media Recorder does the recording and the media processing of the incoming media streams. By default, the Recording Director module is always connected to the local Media Recorder module within the same service, with priority 0.
On the other hand, the Recording Director can be connected to other Media Recorder modules, hosted by other Verba Unified Call Recorder services on other servers. The Recording Director module can do mid-call failover between the connected Media Recorders.
Multiple Recording Director connections can be set up using multiple SIP trunk / CTI connections. Each Recording Director can have his own Media Recorder, or they can have common Media Recorders also. If a Recording Director doesn't have an available Media Recorder, it responds with SIP 503 to the incoming SIP sessions, so it initiates a SIP trunk failover where it is possible.
The services also can be cross-connected.
The priorities of the Media Recorder connections are adjustable. The Media Director always using the Media Recorder with the highest priority. If the Media Recorders have the same priority, then there will be load-balancing between them. If a Media Recorder in use goes down, then the Recording Director can reassign the call to another Media Recorder, providing mid-call failover.
The JTAPI service connections (if used) have to be configured on the servers used as Media Recorders.
Configuring Media Recorder connections
Preparations
On all Recording (or Single) Servers the Verba Unified Call Recording service has to be activated. The ones that receiving the SIP connections going to function as Recording Directors.
If the Data models is used and the recorder server clocks are not synchronized, the Media and CDR records will be recorded with different timestamps, and the playback will not work as expected.
Configuring remote Media Recorders
The local Media Recorder should not be added as a remote Media Recorder. If it is added and communication is not done via memory as desired, it can lead to unexpected issues, especially with VOX triggered CDR keeping
Step 1 - In the Verba web interface go to System / Servers, select the Recording Server which functions as a Recording Director, and click on the Change Configuration Settings tab.
Step 2 - Under the Unified Call Recorder / Recording Providers / Remote Media Recorders node, click on the 
icon at the Remote Media Recording Servers setting.
Step 3 - In the right panel select the remote Media Recorder server at the Host setting. Provide the username and password configured in the Verba Unified Call Recorder Service on the Recording Server acting as a Media Recorder (Unified Call Recorder / Media Recorder / Incoming Connection, User and Password). Set the Port to 10500 and set the Priority.
Step 4 - Click on the Save button at the bottom. If there are multiple remote Media Recorders, then repeat steps 2-4.
Step 5 - Save the changes by clicking on the 
icon.
Step 6 - A notification banner will appear on the top. Click on the click here link, so you will be redirected to the Configuration Tasks tab. Click on the Execute button in order to execute the changes.
Configuring the local Media Recorder
The Recording Director module is always connecting to the local Media Recorder module within the same service, with priority 0.
The Media Recorder module can be turned off by setting the Media Recorder Enabled setting to No under the Unified Call Recorder \ Media Recorder \ Basics node.
Override media recorder selection
AVAILABLE IN 9.5 AND ABOVE
The load balancing and mid-call failover are enabled for turret integrations by default, in some recording scenarios, it is recommended to disable it.
To disable the remote recording for an integration:
Step 1 - In the Verba Web Interface go to Administration > Verba Servers > Select your Recording (or Single) Server which functions as Recording Director > Click on the Change Configuration Settings tab.
Step 2 - Under the Unified Call Recorder \ Recording Providers \ Integration node and change the Force Recording Media on Director to Yes.
Step 3 - Save the changes by clicking on the icon.
Step 4 - A notification banner will appear on the top. Click on the click here link, so you will be redirected to the Configuration Tasks tab. Click on the Execute button in order to execute the changes.
In case of active/active (2N) recording cross-connecting the services is not recommended, the best practice is to keep the servers independent of each other.
PBX specific high availability options
Although Verba supports both Recording Director and Media Recorder failover, the actual possibilities are highly dependent on the phone system.
Cisco
With the Cisco Unified Call Manager, both the Recording Director (SIP connection) failover and the Media Recorder mid-call failover is possible. The number of the SIP connections is unlimited, and the SIP sessions are independent of the media sessions, therefore the failover of the components can be done independently.
Avaya
Avaya does not support active/passive (N+1) DMCC connection failover, instead, it does active/active (2N) recording. The recording will be started at each connected Avaya Recorder service. The DMCC connections are independent of the media sessions, therefore in case of a DMCC connection problem, the recording won't be interrupted at the corresponding Media Recorders.
BT IPTrade
BT IPTrade supports both active/passive (N+1) and active/active (2N) recording. The media sessions are tied to the SIP connections but can be handled separately. Media Recorder load balancing is possible, but in case of a SIP connectivity problem, IPTrade closes all corresponding ongoing media sessions. Mid-call failover is not possible on the Media Recorder level. Instead, in case of Media Recorder fault, the Recording Director closes the SIP connection, and IPTrade reestablishes all ongoing media sessions with another Media Director (and Media Recorders).
If TPO recording is utilized, the re-establishment of sessions may cause IP Trade TPO to get stuck and needs a restart to recover. It is highly recommended to use the Force Recording Media on Director described in the Override media recorder selection.
Speakerbus
Speakerbus supports 2N recording only. The media sessions and the SIP connections are tied together and cannot be handled separately. Therefore load-balancing is not possible.
IPC Unigy
IPC Unigy supports 2N recording only. The SIP sessions are independent of the media sessions, so load balancing and mid-call failover are also possible between the Media Recorders.
Broadsoft
Broadsoft supports only one SIP connection, so Recording Director failover is not possible. The SIP session is independent of the media sessions, so load balancing and mid-call failover are also possible between the Media Recorders.