Archive

Posts Tagged ‘clustering’

A Powerless Feature in VMware vSphere

June 1st, 2011 No comments

Distributed Power Management (DPM) is a powerful (powerless, really) feature can reduce host power consumption in a DRS cluster. It works in either manual mode or automatic mode only when DRS is enabled. DPM can place idle hosts into standby mode, or awaken them from standby when more resources are needed.

Like most of the features in vSphere, you can manage them with the APIs. A recent question at the open source vSphere Java API forum asks how to get hold of the DpmBehavior data object. This seems easy but

Cloud Architecture Patterns: Façade VM

November 15th, 2010 No comments

Intent

Provide a single point of contact for a large-scale system consisting of many virtual machines so that they are viewed as one giant VM from outside

Category

Structural

As Known As

Giant VM

Motivation

When a system becomes big, you need multiple VMs to support the workload. For ease of use reasons, external users don’t want to manage multiple connections to each of the virtual machines. Who wants to remember a list of IP or DNS names for a service? Also, you just cannot expect your users to pick up the least-busy VMs for balanced workloads across your cluster of VMs. And to scale your application when your overall workload increases, you want a seamless way adding new capacities without notifying others.

Finally, if you offer a public service, you don’t want to allocate a public IP address for each of your VMs. These days, public IPs are scarce resources and may cost you money.