Looks like the answer is in the release notes (in the known issues):  The following performance metrics are not supported with the REST API:  Disk Metrics:   DiskReads   DiskWrites   SeekDistance  Disk Group Metrics:   DiskReads   DiskWrites
Unisphere for VMAX rest API : some performance metrics in the request body cause the request to fail.  Unisphere version 8.0.1.12  Following is an example (sensitive information replaced with 'xxxx'). When querying Disk metrics, I am requesting (between other things) "DiskReads". The response contains an error message about DiskReads not being valid or something like it. I haven't tried but if I remove DiskReads from the query, I am almost sure I'll have the same problem with DiskWrites. Generally speaking, I have the same problem on many performance metrics, on other objects. Any idea what's going on?  Thanks,  Laurent.  URI : [URL] Request body:  =============== {    "startDate" : 1454355300000,   "symmetrixId" : "xxxxxxxxxxxxxx",   "metrics" : [ "PercentBusy", "AvgQueueDepth", "TotalSCSICommands", "DiskReads", "DiskWrites", "MBReads", "MBWritten", "AvgReadSize", "AvgWriteSize", "ReadResponseTime", "WriteResponseTime", "Seeks", "SeekDistance", "AvgHypersPerSeek", "VerifyCommands", "SkipMaskCommands", "XORWriteCommands", "XORReadCommands", "AvgResponseTime", "MBs", "IOs", "TotalCapacity", "UsedCapacity", "PercentCapacityUsed", "PercentCapacityFree", "AVG_HYPER_PER_SEEK", "AVG_KB_PER_READ", "AVG_KB_PER_WRITE", "AVG_QUEUE_DEPTH", "IO_RATE", "MB_RATE", "MB_READ_PER_SEC", "MB_WRITE_PER_SEC", "PERCENT_DISK_BUSY", "PERCENT_DISK_IDLE", "PERCENT_FREE_CAPACITY", "PERCENT_USED_CAPACITY", "READS", "RESPONSE_TIME", "RESPONSE_TIME_READ", "RESPONSE_TIME_WRITE", "SCSI_COMM", "SEEK_DISTANCE_PER_SEC", "SEEKS_PER_SEC", "SKIP_MASK_COMMAD_PER_SEC", "TOTAL_DISK_CAPACITY_GB", "VERIFY_COMMAND_PER_SEC", "WRITES", "XOR_READ_COMMAND_PER_SEC", "XOR_WRITE_COMMAND_PER_SEC", "USED_DISK_CAPACITY_GB" ],   "dataFormat" : "Average",   "endDate" : 1459539300000,   "diskId" : "xxx" }  Response status code : 502 Response status phrase : Bad Gateway Response text : =============== {    "message" : "java.lang.IllegalArgumentException: No enum constant com.emc.em.spa.util.KpiName.DiskReads" }
Unisphere for VMAX rest API : some performance metrics in the request body 
cause the request to fail