With the amount of work I have been doing on vCOps
, I do get a number of questions on various platforms such as Twitter, Facebook, LinkedIn and on my posts around various things which people want to know. Although a great solution, it was not marketed the way it should have been and hence the awareness is missing. This is my attempt to make it easy for people to get some of the basic answers about the product on a single page.
I will keep updating this PAGE as and when I get questions which I think will benefit the larger audience and will post it through the twitter and other social media channels. We will go in descending order to ensure you get the latest FAQs on the top of the list.
vCenter Operations Manager 5.X – Frequently Asked Questions
*** Last Update Date – 17th April 2014 ***
FAQ 2 – () – I just want to know one thing, how can I get a report of actual memory usage of VMs ? Because all the reports generated by the vCOP are depend on Active memory or some other thing…
RESPONSE – Great question… But what we need to understand is that Memory Usage is a thing of the past. vCOps uses the concept of derived metrics and not the primitive metrics such as usage. Usage is a virtual world can be incorrect data as we are taking about a shared infrastructure where, Memory & CPU are shared. Hence it will make sense to look at DEMAND rather than usage.. Demand is a derived metric which is a combination of Active memory + overheads.. That’s the real utilization from the Guest OS perspective. Would recommend vCOps Analyze and Predict training which can help you drill down in the concepts…
FAQ 1 – () – One thing I want to know, how can we tell to our customers to adjust allocated memory by analyzing DEMAND in order to maximize the memory utilization, because DEMAND is very small compare to allocated memory.As an example allocated memory to an Exchange Server is 16 GB, but DEMAND will be 3-4 GB !!!!, I just want to know a proper metric or an equation to suggest our customers like ” 10 GB memory allocation is enough to this Exchange Server “
RESPONSE – I think your query is more related to the Over-sized VM Report which can sometimes be crazy to show to an application owner as it completely gives recommendations on the basis of Demand and not usage.
There are 2 things which we need to keep in mind:-
a) vCOps in its current Avatar, does not have the option to key in the bare minimum requirement for the OS or an application which is required to get support from an OS or Application vendor, hence you cannot just blindly rightsize the VM as per the recommendation in the report. You need to start with shaving off 15 to 20% to see the application behavior but yes, you cannot go below supported minimums. Eg. you cannot go on 512 MB of RAM on a Windows 2008 Server OS, since the minimum required and supported by MS is 2GB. I would so any rightsizing by taking the minimum required for support + demand + 20% buffer for Peaks and then come out with the final size.
This might be an enhancement you might see in the future releases.
b) Another thing to keep in mind is the policy which you have defined for the Oversize VM calculations. It is the most understood thing in the product and I will work on a blog post soon to explain it.. Just to let you know, I recommend a setting of 80% instead of the default 1% of the time. That will give you more real world results.
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