The global formula to calculate MCS storage capacity planning, according to the Citrix knowledge base (see Machine Creation Services (MCS) Storage Considerations), is the following:
(number of defined storages in selected hosting connection * number of max. expected updates until complete reboot of machine catalogue and 12h wait time * actual image size * number of machine catalogues using this image) + (number of max. CCU * 15% from image size) + (number of vm´s * 16 MB) (+ for VMware (number of vm´s * VM swap file *2))
This formula has been proven to be quite reliable over the years. It can be ventilated in a table to make it visually easier to understand. Note that the units is in MB, not GB.
We will take an example of a single LUN in the shared storage (the Hosting connection) used for both OS Storage and Temporary storage, with 3 machines catalogues (Test, UAT, Production), and 2 simultaneous disk updates. The target is 30 virtual desktop agents (Multisession hosts, Windows Server) and 300 users. The VMware swap file will be standard size of 512 MB and the identify disk is always 16 MB with MCS:
In this example, for the MCS storage capacity planning, the formula is the following:
(1*2*122880*3) + (300*18432) + (30*16) + (30*512*2) = 6298080 MB.
It is possible to use Google to calculate the formula for you, just to let this good old calculator at rest:
The storage capacity planning on SSD to provision is equal to 6.3 TB.
It is realistic to target an initial provisioning of 6 TB with Thin Provisioning.