VMWare 6 ESXi
/boot partition 2 GB
/ partition 25 GB
/swap partition 4 – 8 GB
/var partition 250 GB – 330 GB.
I create 4 virtual partitions for my WordPress server. I can expand each one as needed. I have had web sites of over 500 GB in /var. /boot could be as small as 500 MB. I usually give it 1.5 GB – 2 GB. The root partition or / hold your other components like the database server.