There are a few vSphere features that I really found myself taking for granted until they had enhancements added to their base technology. How about you? Are there any features that you simply don’t think about anymore? You know, ones that just work and have been around and used in best practices for a good while now? Well, for me personally, those features are vMotion and High Availability (HA). Both of these features have been enhanced in vSphere 6.0.
Articles Tagged with HA
By Greg Schulz, Server and StorageIO @storageio
IO, IO, it’s off to storage and IO metrics we go shifting gears a bit from the recent four part series around SSD topics for physical and virtual environment. A while back I did a post about Why VASA is import to have in your VMware CASA along with another piece about Windows boot IO and storage performance impact on VDI planning. Among other things those two pieces have in common is a theme around the importance of storage and IO metrics that matter.
I saw a question get posted on twitter that kind of intrigues me a little. The question was pretty straight forward. “How many virtual machines should I be able to run on a host?” That is really a fair question in itself but what I find intriguing is that this is the first question he asks. Is this really the first thing administrators think to ask when designing their environment? After all there is no set formula on how many virtual machines you can run on a host. You can be a little more exact when working with VDI because for the most part all the virtual machines would be set up pretty much the same way and the numbers can be a little more predictable. That would not be the case when working with server virtualization. You are going to have servers all with different configurations and amount of resources provisioned to the virtual machines. This variation is what will change your slot count and the amount of virtual machines you can run on the host.
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 host 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.
This is a lofty goal, and we are not quite there yet, but we are further along than when I wrote VMware ESX Server in the Enterprise: Planning and Securing Virtualization Servers when ESX 3.0 first shipped. But what has really changed, as I talk to people, much of the automation is still done by hand coding specifics to all environments. I think we are close, and take some of the real innovations as writ and move on from there.