Chances are if you’re reading this blog, you’re already familiar with virtualization and more specifically, VMWare’s latest offering; vSphere (ESX 4.0).  As the nitty gritty details are readily available on the VMWare website, I’ll skip the fluff and give my personal impressions of the features I’ve used so far.

The Upgrade
     I started using ESX in 3.0, so this wasn’t my first time movin’ on up to the upper east side, or in this case a newer and better version of VMWare ESX.  The upgrade of vCenter server went poorly, having plugin issues and database issues that at the time did not have widely known fixes or workarounds.  I don’t care about performance history all that much so I did a full uninstall/reinstall of vCenter, including the database, and all was well.   Upgrading the ESX hosts was so easy, I won’t waste much time talking about it.  Using upgrade baselines in vCenter I plugged the ESX4 iso in, ran a scan, then individually remediated each of our four hosts in the same manner that I would when installing patches.  It was that easy. » Read more: vSphere First Impressions

I can think of plenty of scenarios where limits would come in handy, and none of them apply to my implementation (yet) so I’ll spare you my speculative wisdom.  I have only one piece of advice regarding this setting, and it’s: DON’T make the mistake of assuming that zero and unlimited mean the same thing, because they don’t.

In summary: zero = the end of the world as you know it, so don’t do it, and especially don’t do it to all of your VMs at once.  Trust me on this.