perUnitStorageThroughput   
  Required with PERSISTENT_1 and PERSISTENT_2 deployment types using an SSD or HDD storage class, provisions the amount of read and write throughput for each 1 tebibyte (TiB) of file system storage capacity, in MB/s/TiB. File system throughput capacity is calculated by multiplying file system storage capacity (TiB) by the PerUnitStorageThroughput (MB/s/TiB). For a 2.4-TiB file system, provisioning 50 MB/s/TiB of PerUnitStorageThroughput yields 120 MB/s of file system throughput. You pay for the amount of throughput that you provision.
Valid values:
- For - PERSISTENT_1SSD storage: 50, 100, 200 MB/s/TiB.
- For - PERSISTENT_1HDD storage: 12, 40 MB/s/TiB.
- For - PERSISTENT_2SSD storage: 125, 250, 500, 1000 MB/s/TiB.