How to improve VM creation time with HPE Helion CloudSystem in an OpenStack Environment
In Helion CloudSystem, when large number of computes are registered to cloud (>10 computes), the Virtual machine boot time may degrade when there are large number of concurrent requests. This is because virtual machine provisioning gets scheduled in the hypervisors in stacking mode by default. In stacking mode, VMs are provisioned in set of 5 compute nodes. The scheduler picks up next set of 5 computes only when the first set of computes is completely exhausted, this in turn increases the boot time for the virtual machine when the concurrency of nova boot request is more than 5.
To improve the VM boot time in a large scale environment, scheduler configuration can be modified from stacking mode to spreading mode. In the case of Spreading Mode, the VMs are provisioned on the computes where the largest resources are available. For example, in a cloud with 20 identical compute nodes, and if there are 20 concurrent boot requests, the scheduler schedules the VM creation on all 20 compute nodes in parallel as against stacking mode. This improves the overall boot time of VMs.
Read the entire article here, How to improve VM creation time with HPE Helion CloudSystem in an OpenStack Environment
via the fine folks at HP Enterprise.