Workload Balancing (WLB) and its functionality has
been removed from XenServer version 6.2 and higher. Applications, code, or
usage that depend WLB will not function in XenServer version 6.2 and higher.
Balancing is enabled, if you take a physical host offline for maintenance (that
is, suspend a server by entering Maintenance Mode), XenServer automatically
migrates the virtual machines running on that host to their optimal servers
when available. XenServer migrates them based on Workload Balancing
recommendations (performance data, your placement strategy, and performance
If an optimal
server is not available, the words
here to suspend the VM
appear in the
dialog box. In this case, Workload Balancing does
not recommend a placement because no host has sufficient resources to run this
virtual machine. You can either suspend this virtual machine or exit
Maintenance Mode and suspend a virtual machine on another host in the same
pool. Then, if you reenter the
dialog box, Workload Balancing might be able to
list a host that is a suitable candidate for migration.
Note: When you take
a server offline for maintenance and Workload Balancing is enabled, the words
"Workload Balancing" appear in the upper-right corner of the
Maintenance Mode dialog box.