Vmware DRS (Distributed Resource Scheduler)

DRS -Distributed Resource Scheduler

Vmware DRS cluster is a collection of multiple ESXi hosts and virtual machines with shared resources.

When you add host in DRS cluster, the host resource becomes part of cluster resource.

Following are the DRS capabilities.

Load Balancing

Auto load balancing of virtual machines with respect to CPU and memory utilization across ESXi host within cluster. DRS monitors the resource utilization and moves the virtual machines to another host where it gets the ideal resource. Its uses vmotion technology and its plan vmotion of virtual machines.

Power Management

Distributed Power Management (DPM), if enable in cluster its power off the ESXi host server when its in ideal state while during peak hours whenever cluster requires more resource its power ON the server. we can say its saves power by shutting down the physical (ESXi host) server. Its might uses vmotion to migrate the virtual machines to other hosts.

Virtual Machines Placement

DRS comes with affinity(together) and Anti-affinity(Separate) rules for placement of redundant and dependent virtual machines as needed.

Benefits of DRS

• Auto load balancing of virtual machines that mean no need to manually initiate vmotion.
• Prevents virtual machines from monopolizing all resources
• Offers most efficient user of server hardware.
• you can create migration rules to keep virtual machines together or apart.
• DRS can auto place new virtual machine in the cluster.

Requirement of DRS

• vShpere Enterprise or Enterprise Plus licence.
• Shared storage between hosts.
• All virtual machines in the cluster must be on that shared storage.
• DRS uses the vmotion so its needs to work between hosts CPU's to avoid compatibility issues checkout the Enhanced Vmotion Compatibility (EVC).