In previous post I discussed various sizing approach and how it gets influenced using allocation models. Let me continue from the same post. As we already have decided on allocation models and how much each Organization vDC will use and in what way. lets move further.
Previous post missed on one very important aspect. It is a relation between Catalog and VM offering. From above table it is not clear how many VM’s and which sizes are available for the particular BU. It leaves lot of room for consumer to do this calculation. To address this problem you can provide number of small, medium, large size you can create from this, and then assist them fixing the VM template accordingly.There is screen (shown below) in vCloud director which shows this status but it is only vCloud Administrator (only user who can create Organization vDC), who can see it. It is of little use for Organization Administrator
So how do we solve/help organization in deciding VM’s and its sizing they can offer or get most out of it. Let’s try to answer the below question
“How many VM in HR BU we can fit and of which Sizes”
I have created a tiny excel sheet with simple formula. Below part have Virtual Machine catalog defined. Here goal is to fit VMs either using 256 GB RAM or 256 GHz. You can manipulate number of VM’s or you can change the VM catalog as per your fit to consume maximum of both compute section i.e. CPU and Memory
In above figured I have populated Virtual Machine catalog in standard T-Shirt size naming convention. This is very simple excel sheet which is picking up vCPU and Memory defined in Virtual Machine Catalog table.
e.g. As highlighted in table above for M size, we have 2 vCPU and 4 GB RAM configured. So for 5 VMs we will need 10 vCPU and 20 GB RAM. Similarly for other VM size it follows the same formula. In the end you get total VM as 44 with total 128 vCPU and 256 GB RAM
To fit the compute (256 GHz or 256 GB RAM) you can change the VM catalog size and continue to do so once you each either of the limits are reached. In above table have reach 256 GB RAM limit. But you can very well try to reach CPU limit as well by manipulating VM size in the catalog.
I have uploaded the excel sheet on my google drive, will be available on request. I’m just doing this to know how popular it is getting
Once you are done with this permutation and combination you would come up with some standard sizes. Just ensure you create catalog of only such sizes. This will allow you to control and monitor the capacity of organization.
So key take away is you can definitely create VMs of your own sizes to make most out of the capacity you are buying. I have provided excel sheet based formula which will make things bit easier.