Most of us will be familiar with the df command. But in ESX, you use the vdf command, located in /usr/sbin. Running the vdf command will net you similar output to what you see with df. Simply run the following to see free space on each of your disks:
vdf -h
You can also list all of your data stores to correlate the vdf output with esxcfg:
/usr/sbin/esxcfg-scsidevs -c
Or to list LUNs:
/usr/sbin/esxcfg-mpath -L
BTW, if you’re running out of free space, in my experience, first look to your snapshots and check how much space they’re consuming…