client = paramiko.SSHClient()
client.load_system_host_keys()
client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
client.connect("1.1.1.1",  username=username, password=password)
stdin, stdout, stderr = client.exec_command("set -units GB")
stdin, stdout, stderr = client.exec_command("vol show -vserver vs1 -volume test_volume -fields size")
return stdout.read()

vserver                          volume             size
 ------------------------  ------------------         ------
 vs1                       test_volume               1.07TB

test01::> set -units GB

 test01::> vol show -vserver vs1 -volume test_volume -fields size

 vserver                          volume             size
 ------------------------  ------------------         ------
 vs1                       test_volume               1100GB