Physical disks WMI get с ключом wmi.getall[root\cimv2,"select * from win32_perfformatteddata_perfdisk_physicaldisk"] получает все данные про все диски.
этот ключ возвращает json типа такого [{"AvgDiskBytesPerRead":"0","AvgDiskBytesPerTransfer":"0","AvgDiskBytesPerWrite":"0","AvgDiskQueueLength":"0","AvgDiskReadQueueLength":"0","AvgDisksecPerRead":0,"AvgDisksecPerTransfer":0,"AvgDisksecPerWrite":0,"AvgDiskWriteQueueLength":"0","CurrentDiskQueueLength":0,"DiskBytesPersec":"0","DiskReadBytesPersec":"0","DiskReadsPersec":0,"DiskTransfersPersec":0,"DiskWriteBytesPersec":"0","DiskWritesPersec":0,"Name":"_Total","PercentDiskReadTime":"0","PercentDiskTime":"0","PercentDiskWriteTime":"0","PercentIdleTime":"94","SplitIOPerSec":0},