如何比较存储大小的字符串

Question

I am trying to write a wrapper script in python to extend logical volumes. I am giving it a desired size, and it's able to get the exiting size.

existing_dict{} = {'root': '5.00g', 'opt': '10.00g', 'var': '20.00g'}
desired_dict{} = {'root': '10g', 'opt': '20g', 'var': '100%'}

How exactly do I compare the existing size value to the desired size value so I can take some action on it? So say the desired is same as existing then do nothing. If existing size is bigger than desired size then throw an error. If desired size is bigger than existing size, try to lvextend. Or, lastly, if the desired size is a percentage, then perform the lvextend with the percentage value.

Answer 1

I think you can start with breaking down the string to kb or bytes, and then compare them eg 5.0 G = 5x1024x1024 bytes

def convert_to_bytes(size):
    return size*1024*1024
existing_size = convert_to_bytes(size1)
required_size = convert_to_bytes(size2)
if existing_size < required_size:
    #resize
else:
   raise Exception()