The capacity of a service module is measured in blocks. If a LUN is created in DeviceManager with a capacity measured in MBs, GBs, or TBs (accurate to a maximum of three digits after the decimal), the value is rounded down. After the LUN has been created, the LUN capacity obtained from the service module is also measured in blocks and then converted to a value in the requested unit of measurement, accurate to a maximum of three digits after the decimal point. For example, 68.078 GB is converted into 73098195894.272 bytes and then 142769913.856 (73098195894.272/512) blocks. The value that is actually sent to the service module is 142769913.
After a LUN query, the returned number of blocks is also 142769913, which can be converted into 73098195456 (142769913 x 512) bytes.
To ensure that the capacity is displayed normally, the capacity measured in bytes is further converted into 68.077999591827392578125 GB. This becomes 68.077 GB because the value only needs to be accurate to three digits after the decimal point. Therefore, if the capacity entered during LUN creation is not an integral multiple of a block, the displayed capacity of the LUN will be inconsistent with that specified during creation.
Applicable Versions
OceanStor V3 V300R001
OceanStor V3 V300R002
OceanStor V3 V300R003
