How to Create a Sparse File Pool on a Laptop Computer

If you do need to estimate like this, your best bet is spin up a VM or have a computer that is already using ZFS or has ZFS installed. You use the truncate command to make a bunch of sparse files that are the size of the hard drives you want to use. So very easy to create 20 10 terabyte sparse files in your slash TMP and it won't actually take up any disk space. It will exactly match what happens when you use real hard drives because you can create the files to be exactly the same number of bytes as a hard drive.