Adding a standby server to your Archiver role minimizes the downtime of your live video if a hardware failure occurs.
How Archiver failover works
If the server hosting the Archiver role fails, you lose access to live video and archived video. Live video is disabled because the Archiver controls the video units. Access to archived video is disabled because your archives can only be accessed through the Archiver that created them (even if your database server is not the computer that failed).
- You can assign a primary server, a secondary server, and a tertiary server to an Archiver role. This is especially useful in multi-site systems, as you can protect the primary and secondary servers at a local site with a tertiary server located at a remote site.
- The primary, secondary, and tertiary servers must each have their own database, hosted locally, or on another computer.
- To make sure that the video archived by the primary server is still available if it fails to a secondary or tertiary server, you must turn on redundant archiving. This ensures that all servers can archive video at the same time, and that they each manage their own copy of the video archive. You can set up redundant archiving on all cameras managed by the Archiver role, or protect just a few important cameras
Careful load planning for failover
If failover occurs, the performance of a standby server might be affected by the additional archiving load (number of cameras, video quality, and so on) from the new Archiver role. If the standby server hosts other roles, this also affects archiving capability.
- If the server has other functions, it might not be able to absorb the full load of another server.Tip: To lessen the failover load on a server, create multiple Archiver roles with fewer video units each. Also, configure all the Archivers to share the same primary server, but to fail over to different secondary or tertiary servers.
- How long is a typical failover expected to last? The longer a failover lasts, the more additional disk space you need to reserve for archiving.
- A server can handle more video units when only command and control functionality is needed. If video archiving is not important on all cameras, you can associate all important cameras to one Archiver role and give it a higher archiving priority than the rest. That way, if multiple Archiver roles fail over to the same server at the same time, archiving will be maintained for the important cameras.
Limitations of Archiver failover
The failover process can take 15-30 seconds for cameras to come back online. During this time, live video cannot be viewed and Auxiliary Archiver roles do not record. However, the gap in recorded video is much shorter: no more than 5 seconds.