vSAN Effective Capacity – Quick and Dirty Sizer Tool

Found this online tool to quickly approximate how much datastore capacity you can get from a certain number of vSAN hosts with certain configuration. I think this is very useful in the case where you already have certain number of physical hosts with vSAN compatible disks, and you want to determine how much capacity you can get from it, and the capacity of cache disk you need to provide to fulfil the 10% recommendation of cache capacity compare to consumed storage (reference). In my experience, I have seen couple of customers where they already have considerably new server hardware with vSAN compatible components where they want to see what they will get if they use vSAN. Please note that VMware has official vSAN Sizing Calculator where you can get recommendation of the hardware specification you need to provide to accommodate certain number of workloads (VMs). This online tool is very easy to use. In this example, let's say you have 10 server, where each server have 7 x 400GB SSD disks. You have checked that those server, and the SSD disks and disk controller, are compatible with the latest vSphere/vSAN. You want to ensure data availability in the event of component failure but still get the maximum possible capacity, so you configure the sizer appropriately according to your requirements and select RAID5 (Erasure Coding). In couple of clicks, you will get the result. You'll see that from the available hardware you'll get 14.02 TB from total of 10 vSAN hosts. Which means, for the cache disk, you'll need to have at minimum 1.402 TB (10% x 14.02TB). That cache capacity needs to be distributed into 10 hosts, or around 140 GB (1.402 TB/10) per host. That's it for now. I hope that's informative for you. via Latest imported feed items on VMware Blogs https://ift.tt/2sgQtsE If New feed item from https://blogs.vmware.com/feed, then send me an email at kr