There have been a certain amount of discussions lately regarding optimal and efficient implementations of ESX Server, VMware’s flagship product in terms of x86 hardware virtualization. This document is a guide or a basis for a discussion related to the best practices in terms of the scalability of an ESX Server implementation on IBM xSeries and BladeCenter servers.
In this document, we focus the discussion around two major scenarios: the so-called scale-up implementation and the scale-out implementation. These are terms that are used often today that basically describe the usage of an architecture, either based on one or few big x86 server systems, or based on many smaller x86 server systems. The former being defined as a scale-up solution (that is, you have to add components and resources to the big system in order to achieve scalability) and the latter being defined as a scale-out solution (that is, you have to add new server systems to your “server farm” in order to scale it accordingly to your needs).
The objective of this document is to create the basis for a wide understanding of what the advantages and disadvantages are for both approaches without having to compromise our analysis and match it with a limited set of products. This should ensure the readers that our analysis will be as agnostic as possible.
We assume that readers of this paper have an understanding of the VMware products — specifically ESX Server, VirtualCenter and VMotion.