WholesaleBackup servers can be load balanced for environments where you either wish to (a) serve more backup clients then a single server can handle or (b) be able to take a single server offline for maintenance and without effecting availability to your backup clients. You can use (1) round robin DNS settings; (2) a dedicated load balancer device, whether it is a commercial device from a manufacturer such as f5, a open source device running pfsense, a home brew box running openbsd (and using pf); or (3) using Microsoft's server based load balancing.
Load balancing basically involves having your WholesaleBackup Server traffic being serviced by a pool of servers. For this to occur, there needs to be a "load balancer" to direct incoming WholesaleBackup TCP traffic to a particular server and each server needs access to every accounts data folders and so are usually configured identically except for their internal IP addresses.
DNS round-robin rotation is by far the simplest way to spread traffic over your servers. This could be configured with your DNS provider for your FQDN (sending your clients to different public IP addresses), via your firewall (if it supports it), or internal to your LAN (behind your firewall) by directing traffic (see http://technet.microsoft.com/en-us/library/cc787484(v=ws.10).aspx for example).
In addition, Microsoft has implemented a sophisticated framework for load balancing among clusters of servers and created a "Network Load Balancing Technical Overview" which introduces and describes all the needed technical concepts where you can access this document at: http://technet.microsoft.com/en-us/library/bb742455.aspx as well as another overview (originally written for Windows 2003) at http://technet.microsoft.com/en-us/library/cc756878(v=ws.10).aspx. In addition, Microsoft provides a "Network Load Balancing Deployment Guide" which can be accessed at http://technet.microsoft.com/en-us/library/cc754833(v=ws.10).aspx.
From our experience, utilizing DNS round robin or a seperate load balancing device, such as one running the free utility pfsense (which can also be used as your firewall) is easier to install and manage for IT professionals who are not immersed in Microsoft's server technology, network load balancing, and advanced network switch configurations.
Whatever load balancing technology you choose to implement, all you are doing is (a) directing TCP traffic for the port your WholesaleBackup server listens on to a WholesaleBackup server listening on that TCP port, (b) being sure each server has WholesaleBackup server installed and configured to share the same WSBU.db and WSBU.csv (and if used WSBU.bat WSBU_CC.bat files) on a network share, and (c) being sure the network path to each WholesaleBackup client's data is identical across each server.
Please contact our sales department if you wish to engage our consulting services team in assisting you in choosing, configuring, and managing network load balancing.