Wednesday, 16 November 2016

Virtualization Oversubscription - What’s so scary? (1 of 20)


Overcommit vs Oversubscribe

When I wrote the Title and Synopsis for this blog series I happened to choose the word oversubscription.  It’s been pointed out to me that many people refer to “overcommit” rather than “oversubscribe”. 

Both words appear to be in use to describe this and Google does some nice work to return results using either option.


What led me here? 
In my role with Metron I get to visit lots of different people working in lots of different industries.  They are mostly capacity managers working in IT departments though, so there is some common ground.

Clients
       “Oh, we don’t oversubscribe”

Over the past year I’ve had a number of mildly frustrating conversations with organisations.  These tend to be newer and/or don’t have a good history of Capacity Management.  The frustration has been around ‘Oversubscription’ in virtualised environments. 
I’ll start talking about how we can monitor the environment to ensure good performance in the future.  When they’ll stop me and say, quite proudly, “Oh, we don’t oversubscribe, we don’t want to impact performance”.  The pride is almost the worst part.  They’ll beam a smile at the senior staff as if to say “We’ve got this, don’t worry”.  They aren’t concerned about the overspend that’s required to have that attitude.

Ultimately there is a fear in these departments that oversubscription = poor performance. I'll be looking at the fear and misunderstanding around this on Friday.

In the meantime there are still a few places available at our VMware Capacity and Performance essentials online workshop, don't forget to book your place now.


http://www.metron-athene.com/services/online-workshops/capacity-management-workshops.html

Phil Bell
Consultant


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