xen-orchestra/load_balancing.md

Load balancing

Load balancing is a feature coming for Q2 2016.

The goal here is to distribute the VMs load in the best way possible on your servers.

Because Xen Orchestra is connected to multiple pools and XenServer supports live storage motion, we can imagine load balancing on a whole XenServer infrastructure (even between remote Data Centers).

First challenges

We are already capable to gather the metrics from all the hosts and VMs. But we need now to:

• analyze the global load
• detect bottlenecks
• compare to user limits
• act accordingly

There is also a lot of unknown parameters:

• a live storage motion could be very long on remote DC if your bandwidth is low
• avoid to made worse than no load balancing (this is easier than you think!)

The issue is opened here.

Steps

• xo-analysis get stats from xo-server and build reports/alerts
• xo-director get reports/alerts
• xo-director migrate VMs from various hosts (and even stop "useless" hosts)

Resources

The Citrix WLB Admin guide: http://docs.citrix.com/content/dam/docs/en-us/xenserver/xenserver-60/XenServer-6.0.0-wlb-userguide.pdf