A lot of you probably have a sheet or formula, or maybe just a hard number in your head of how many vm’s you can run on a single server. Some of that could be based on memory, core to vcpu ratio’s or it could just be based on, well that is what works best for me. Either way you have some idea what to expect from your servers, but what about your storage? For some of you this is really not a big issue, because you have scalable, grow-able storage. But for some it could be, either way I put together a spreadsheet that might help.
The sheet takes things like RAID level, number of disks, disk size, LUN or volume size and server memory into consideration. This may or may not be helpful to you, but I wanted to put it out there just the same.
Here is a screen showing a server memory vm count. I did this to give me a rough idea of where my memory utilization was going. Now for hypervisors that support some type of memory sharing or management this may not be very useful, but if you are looking to get a certain memory utilization this might be useful.
Based on your vm HD size this portion will let you know how much storage space you will need. This example is based on a 30G vm HD and the Total Storage is in GB. So if you have 5 vm’s you would need about 180GB of storage.
I think you get the idea behind this, but if you have any questions please post them in the comments or send me a note via the contact form and I will try and help out the best I can.
You can download the sheet here.