Today I attended session VSP1682 ‘VMware vSphere clustering Q&A‘ hosted by Frank Denneman, Duncan Epping and Chris Colotti.

After a short introduction the Q&A started and below you will find my top 10 questions.

Q1. Are the old, vSphere 4, constraints in vSphere 5 still current?

Until vSphere 5 the best practice is a maximum of 8 hosts in a cluster, because of linked clones in VMware View and the primary/secondary ESX(i) hosts setup in an HA cluster. In vSphere 5, VMware changed this to a master/slave setup. When the master ESXi host goes offline a new master is elected within 15 sec. So, the cluster boundary limits VMware vSphere had in the past are gone. This is a huge advantage of vSphere 5.0.

(more…)

Last night, after my son’s first birthday,  I checked my missed twitter messages and a retweet from Duncap Epping caught my eye. It was a link to an article from Eric Gray on vCritical about HA for Linux guests on Hyper-V. Now you will probably think, nice an HA for Linux on Hyper-V whitepaper/how-to, but this is not the case.

As you probably know, very little Linux distributions are supported on Hyper-V and therefore no integration tools are available. Because the lack of integration tools Microsoft Clustering Services, the service which provides HA services for Hyper-V, you can not gracefully shutdown an unsupported Linux host and when shutdown MSCS will desperately try to keep the guest up and running. Because of this shortcoming you will have to choose, run HA OR Linux because you can not run both.

A complete desciption can be found here in Eric Gray’s article on vCritical.com. If you are considering a Hyper-V implementation you should definitaly read this article.

With all the news and buzz around vSphere it’s easy to get carried away by all the new stuff appearing. But even with all these new features we still need to think about High Availability and how to design the infrastructure.

Everytime we design a virtual infrastructure we design it for high availability. We enable HA, we put in a lot of network cards etc to make the infrastructure resilient. Even vSphere brings more high availability options like FT.

But what IS high availability? According to Wikipedia it is:

a system design protocol and associated implementation that ensures a certain absolute degree of operational continuity during a given measurement period.

Well, nice definition, but what does this mean for designing a infrastructure? (more…)

Yesterday I ran into VMware HA problems again. With my past HA troubleshooting experiences I thought configuring HA wouldn’t be a problem any more but unfortunately it bit me in the ass again.

We all know VMware ESX implementations where not all information, access, etc is available when you start with the installation. Exactly this was the case at this project. I only had 4 ESX hosts connected to the network and an EqualLogic SAN and the network was limited to the rack so only the ESX hosts and the SAN were connected. The network guys had to establish a connecting to the HQ but to do that the had to change IP addresses.

I installed the complete VMware Infrastructure with the new addresses waiting for the connection to be made so I could add the servers, like vCenter, to the corporate Active Directory.

(more…)

Today we had a very interesting presentation from Citrix. At one point the discussion was about the Citrix’s definition of High Availability.

I really can imagine that this is getting a confusing discussion. VMware says: HA is to resolve a single host failure. Citrix however also calls live migration a form of HA.

I can’t argue with that but to keep the discussions and comparisons clear it is essential to specify what you define as HA. I think both are right, but the trouble is that, when comparing products, people think they have a solution for hardware failure, but instead they can do a live migration.

I hopefully that in the future both parties start using the same names for the same options, or at least explain what their option is.

February 10th I participated in a VMware WebEx on their new vCenter addon, vCenter Server Heartbeat and today the news will be released in Cannes at VMWorld Europe 2009.

vCenter Server Heartbeat is an important addon which creates high availability for vCenter Server. vCenter Server Heartbeat monitors and protects VMware’s management platform against network, hardware, OS or application issues. This fully protects the infrastructure which helps VMware users to deploy critical applications on VMware.

(more…)

Fellow blogger Duncan Epping of Yellow Bricks has added a great section to his site.
The section is called ‘High Availability “Deepdive”‘ and describes all ins-and-out of VMware HA. Have you always wondered how HA realy works, what primary and secondary nodes are, how to setup isolation response and so on? Then you should read Duncans new HA section.

The High Availibility “Deepdive” is subject to change so bookmark it and check back regularly.
Also check out the HA Advanced options if you want to know even more about VMware HA.

Last few weeks I have been very busy solving HA issues at a client site. As you may have read I solved the problems by swapping out the USB sticks and troubleshooting BIOS settings. Now my collegues asked me if I could write down all checks I performed (together with VMware support) to target these HA issues.

(more…)

It may sound a bit strange, BIOS settings causing HA problems…… At the client site were I previously had problems with faulty HP USB sticks I still experience problems. After the problems with the green USBs after 1,5 week we received new black USBs. This seemed to solve our problems, we swapped all USBs, configured all ESXi hosts and build a new cluster and enabled HA. All seemed well untill I updated all hosts with all the latest patches. (more…)

At the same client site where we had the problems with VMware Update Manager and ESXi we are now struggling with HA. We can NOT get it to work and even WMware support can NOT get it to work either. We have been on the phone with VMware support for almost a week now and have tried various fixes but none of them work. We created a hosts-file to rule out DNS problems, we added advanced HA settings like ‘das.allowNetwork[n]‘ and ‘das.allowVmotionNetworks‘, we created new clusters, checked FT_HOST files and deleted all host from the cluster to build it again from scratch. All without positive results.

(more…)

With the release of VMware ESX/ESXi 3.5 and VirtualCenter 2.5 U3 VMware implemented a few interesting changes in it’s HA implementation.  In this document VMware HA and the latest changes are descibed in detail.

This document is intended for experienced HA cluster admins who are planning to migrate to Update 3 as well as admins who are interested in the explanation of some cluster essentials.