Current vCenter Linux Appliance had limitation of maximum 5 Hosts and 50 VMs due to embedded database. With the release of vSphere 5.5, vCenter Server Appliance now uses a reengineered, embedded database that can now support as many as 500 vSphere hosts or 5,000 virtual machines
http://www.vmware.com/files/pdf/vsphere/VMware-vSphere-Platform-Whats-New.pdf