Node statistics

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The following table lists:
  • Performance statistics calculations previously provided by the CIM agent
  • Respective fields in the statistics file that is reported for individual nodes.
Table 1. Calculations
CIMOM field Calculation
TotalIOs READ_OPERATION_TAG + WRITE_OPERATION_TAG
ReadIOs READ_OPERATION_TAG
ReadHitIOs READ_HITCACHE_TAG
WriteIOs WRITE_OPERATION_TAG
WriteHitIOs WRITE_HITCACHE_TAG
Var File name XML field Description
DEVICE_ID_TAG Nn_stats "idx" Indicates the enclosure or node ID
READ_OPERATION_TAG Nn_stats "ro" Indicates the number of Read I/Os
WRITE_OPERATION_TAG Nn_stats "wo" Indicates the number of Write I/Os
READ_HITCACHE_TAG Nv_stats "ctrh" Indicates the number of reads received from other components and processed in read-cache hit
WRITE_HITCACHE_TAG Nv_stats "ctwfw" Indicates the number of writes received from other components and processed in write-cache hit

The following code example shows an illustration of the calculations in a scripting form.

Request
def get_latest_cimom_sample_node_stats(url, username, password):
    xml = get_latest_stats(url, username, password)
 
    fields = { 
        "READ_OPERATION_TAG": {
            "filename": "Nn_stats", 
            "element": "node", 
            "field": "ro", 
            "value": 0},
        "WRITE_OPERATION_TAG": {
            "filename": "Nn_stats", 
            "element": "node", 
            "field": "wo", 
            "value": 0}, 
        "READ_HITCACHE_TAG": {
            "filename": "Nv_stats", 
            "element": "vdsk", 
            "field": "ctrh", 
            "value": 0},
        "WRITE_HITCACHE_TAG": {
            "filename": "Nv_stats",  
            "element": "vdsk", 
            "field": "ctwfw", 
            "value": 0} 
    }
    populate_fields(xml, fields)
    cimom_fields = {
        "TotalIOs": fields['READ_OPERATION_TAG']['value'] + fields['WRITE_OPERATION_TAG']['value'],
        "ReadIOs": fields['READ_OPERATION_TAG']['value'],
        "ReadHitIOs": fields['READ_HITCACHE_TAG']['value'],
        "WriteIOs": fields['WRITE_OPERATION_TAG']['value'],
        "WriteHitIOs": fields['WRITE_HITCACHE_TAG']['value']        
    }
    return cimom_fields
 
pprint.pprint(get_latest_cimom_node_stats(url, username, password))
Response
{'ReadHitIOs': 0,
 'ReadIOs': 19291610,
 'TotalIOs': 39009988,
 'WriteHitIOs': 0,
 'WriteIOs': 19718378}