Guide to Failover, High Availability, and Load Balancing with Cerberus FTP Server

Cerberus FTP Server does not inherently support clustering. However, by utilizing Active Directory or LDAP authentication in conjunction with a hardware or software load balancer (like Microsoft NLB), you can establish straightforward load balancing and failover mechanisms for Active Directory or LDAP authenticated accounts.

Active Directory or LDAP-Based Load Balancing:

For load balancing based on Active Directory or LDAP, each Cerberus FTP Server machine is configured to connect to the same AD or LDAP database. Requests can be evenly distributed across available servers, providing a simple yet effective failover and load balancing solution. Many of our customers have successfully employed this setup to enhance their system's reliability.

Synchronization Capability:

In Cerberus FTP Server Professional and Enterprise editions, a new feature enables the automatic synchronization of user accounts and settings across multiple Cerberus servers. This capability extends to native Cerberus accounts and customizations to Active Directory and LDAP authentication. The synchronization manager, when combined with shared storage between Cerberus FTP Server machines, allows for the creation of multiple active backup and failover servers.

High Availability Options:

The synchronization manager in the Professional and Enterprise editions offers flexibility by allowing synchronization from a primary server instance to one or more secondary server instances. Changes made on the primary server are duplicated on the secondary servers through the synchronization manager.

Load Balancing Exceptions:

• HTTP/S Web Client Traffic:

  • Load balancing for HTTP/S web client traffic poses challenges. The HTTP/S session database is local to each Cerberus machine, requiring load balancers to route connections from the same IP to a specific Cerberus machine.

• Public File Sharing:

  • The synchronization manager, running at defined intervals, syncs settings to secondary active servers. However, load-balanced traffic may result in a user connection sharing a file from a secondary server, creating a potential conflict that does not propagate to other machines. Currently, there is no workaround for this limitation.

Microsoft Network Load Balancer (NLB) Compatibility:

We've tested Cerberus with Microsoft Network Load Balancer (NLB), providing a compatible solution for load balancing.