The storage amount billed in a month is based on the average storage space used throughout the month. Your storage usage is measured in "GB-Months," which are added up at the end of the month to generate your monthly charges.
For example, assume your file system uses 100GB of storage for 15 days in March, and 250GB of storage for the final 16 days in March.
At the end of March, you would have the following usage in Byte-Hours:
Total usage (GB-hours) = [100 GB x 15 days x (24 hours / day)] + [250 GB x 16 days x (24 hours / day)]
= 132,000 GB-Hours
Convert this to GB-Months:
Total usage (GB-Months) = 132,000 GB-Hours x (1 Month/744 hours)
= 177 GB-Months
The total monthly storage charge is calculated below
Total Monthly Storage Charge = 177 GB-Months x $0.30 = $53.10