The Virtualization Practice

Tag Archive for DRS

I have been a big fan of VMware’s Distributed Resource Scheduler (DRS). VMware DRS is a service or feature that will dynamically allocate and balance computing resources across the hosts in a cluster. In all of the environments I have work with so far, DRS has been a fantastic tool for getting and maintaining that balance across all the hosts in a cluster. Recently though I have come across a limitation of VMware’s DRS that is worth mentioning.

The question of whether and how to replace DRS is really a part of the question of what is in the virtualization platform and what is not. Clearly the virtualization platform consists of much more than the hypervisor. VMware would like to define the virtualization platform as all of vSphere Enterprise Plus, and then suggest that vCloud Director and its own performance management solutions are logical extensions of that platform. Enterprises need to be careful about where they draw their own lines in this regard. As VMware is a clear market leader both in terms of product functionality and enterprise installations, VMware needs to be given full credit for the quality of vSphere and its success. However full credit does not need to imply that one is 100% locked in to VMware solution as there is room to pursue third party IT as a Service, Performance Management, and Service Assurance strategies as well as replace/augment components in vSphere.

With the release of vSphere 4.1 there have been some great enhancements that have been added with this release. In one of my earlier post I took a look at the vSphere 4.1 release of ESXi. This post I am going to take a look at vSphere 4.1 availability options and enhancements. So what has changed with this release? A maximum of 320 virtual machines per cluster has been firmly set. In vSphere 4.0 there were different VM/Host limitations for DRS as well as different rules for VMware HA. VMware has also raised the number of virtual machines that can be run in a single cluster from 1280 in 4.0 to 3000 in the vSphere 4.1 release. How do these improvements affect your upgrade planning?

I just finished writing all the content for my next book entitled VMware ESX and ESXi in the Enterprise: Planning Deployment of Virtualization Servers (2nd Edition) which continues the discussion on Dynamic Resource Load Balancing (DRLB). DRLB is the balancing of virtualized workloads across all hosts within a cluster of virtualization hosts without human intervention. This is the ultimate goal of automation with respect to virtualization and therefore the cloud. In effect, with DRLB the virtualization administrators job has been simplified to configuration and trouble shooting leaving the virtual environment to load balance work loads on its own.