Your HealthCheck for Azure assessment will recommend a migration to either a standard storage account or a premium storage account. The recommendation is based on performance metrics on your observed network.
The benefits of premium storage include disks that provide up to 5,000 IOPS and 200 MB/sec throughput, depending on the disk size. To calculate IOPS, we use 256KB as the IO unit size. IO sizes smaller than 256 KB are counted as one unit, and bigger IOs are counted as multiple 256 KB IOs. You will need to select the disk sizes based on your application performance and storage capacity needs. Available are three Premium Storage disk types:
Based upon the above specifications and the observed usage (IOPS, Throughput, Disk Size), HealthCheck for Azure will recommend the appropriate storage type, as well as the appropriate number of volumes of each storage type.
You can review specifications for Microsoft Azure storage types at Sizes for Cloud Services.