I booted into GParted Live so that I could edit the second partition with more accuracy than Terminal and Disk Utility and move it around as necessary.Using Disk Utility, I edited the size of the first partition to 800 GB (from 800.2GB), which brought it down to 800,000,000,000 bytes on the nose, as required.This yielded something like 800.2GB and 2.2TB (but the 2.2 TB was smaller than the 2,199,975,890,944 Bytes required, of course). Partitioned the Drive using Disk Utility, stating I wanted to split it 800 GB and 2.2 TB respectively.So here's how I eventually got the exact sizes I needed: I can't seem to get the first partition, TimeMachine to land on 800000000000b on the nose. I can't understand why I'm not getting the same exact sizes when I'm being so specific with Terminal.Įdit for additional info: Playing around with the numbers, regardless of what I do I am always off by a minimum of 16,384 bytes. The names are identical to the originals and I'm also formatting them in Mac OS Extended (Journaled), like the originals. I used the following command: sudo diskutil partitionDisk disk3 'jhfs+' TimeMachine 800000000000b 'jhfs+' TELUS 2199975886848bīut the result is TimeMachine being 799,865,798,656 Bytes and TELUS being 2,200,110,092,288 Bytes. I figured I could use terminal to specify the exact precise sizes I needed so that both partitions would be the right size and I could RAID hassle-free. Using DiskUtility, partitioning makes the drives a different size than the above by several hundreds of thousands of bytes, so when I try to add them to the RAID set, it tells me the drive is too small. I bought an identical drive so that I could mirror the above in case of failure.

I've got a 3TB drive partitioned like so:

Disk utility partition