Microsoft's Exchange Server has a reputation as being hard to virtualise under hypervisors other than Redmond's own Hyper-V, a state of affairs that has led to more than occasional suggestions that Microsoft might just like it that way.
But of course Microsoft still tries to keep Exchange humming as best it can, so in late April offered this entirely innocuous guide to “Troubleshooting High CPU utilization issues in Exchange 2013” on the Exchange blog.
And there, you might imagine, the matter would usually end, for Microsoft emits a great many blog posts of this type. Indeed, on June 19th it also published a post revealing an update to the calculator it offers for those contemplating the hardware required for an Exchange implementation.
But in June VMware noticed the post and responded with one of its own titled “A Stronger Case For Virtualizing Exchange Server 2013 - Think 'Performance'.”
That post says “We have been aware for several years that Microsoft's sizing recommendation for Exchange Server 2013 is the number one cause of every performance issue that have been reported to VMware since the release of Exchange Server 2013.” The post goes on to acknowledge that Microsoft's done a good thing in helping users to scale Exchange, but also says the calculator offered to size Exchange rigs is a dud. “Sadly, customers who have moved to Exchange Server 2013, using the Calculator's recommendation (or the equally disruptive "Preferred Architecture" design from Microsoft) have been invariably hurt by the unsound recommendation,” writes Deji Akomolafe, a CTO ambassador at VMware.
Akomolafe goes on to take issue with the way Exchange Server “sees” cores, because that leads to Microsoft recommending hosts don't go beyond 24 CPUs and 96GB of RAM. Servers of that size, Akomolafe reckons, represent “multitudinous proliferation of 'itsy-bitsy-sized' silo'ed physical hardware for Exchange Server.”
The virtualisation blogosphere has had a bit of kicking these issues around for a few days now, often dissenting with VMware's view of the matter. Josh Odgers, a Nutanix staffer and holder of two of VMware's top-level VCDX certifications, comes down on Microsoft's side.
Others have pointed out that Akomolafe has form taking issue with Microsoft on how to virtualise its apps, with this post expressing concern about Lync under vSphere.
And Microsoft? It's been silent on the topic since mid-June. ®