Nodes/{name}/info/iohist: GET

Displays the recent I/O history details for the specified node.

Availability

Available on all IBM Storage Scale editions.

Description

The GET scalemgmt/v2/nodes/{name}/info/iohist request gets the recent I/O history details for the specified node. It lists whether the data or metadata is being read or written, the distribution of I/O sizes, and I/O completion times for individual I/Os. The information that is displayed can be used in performance tuning and troubleshooting. For more information about the fields in the returned data structure, see mmdiag command.

Request URL

https://<IP address or host name of API server>:<port>/scalemgmt/v2/nodes/{name}info/iohist
where
nodes
Specifies the resource for the GET call. Required.
iohist
Specifies the information that is required from the resource.

Request headers

Accept: application/json

Parameters

The following parameters can be used in the request URL to customize the request:
Table 1. List of request parameters
Parameter name Description and applicable keywords Required/optional
name The name of the node. Required.
verbose Extra columns of information are displayed in the response output if this value is set to True Optional.

Request data

No request data.

Response data

{
  "mmDiagIohistParams": [
    {
      "bufType": "string",
      "comment": string ,
      "context":string,
      "devName": string,
      "disk": string,
      "info1": "string ",
      "info2": "string",
      "ioStartHour": "string ",
      "ioStartMin": "string",
      "ioStartSec": "string ",
      "ioTimeMS": "string",
      "ioType": "time ",
      "nsdNode": "string ,
      "rw": "string ,
      "sectorNum": "string ,
      "thread": "string }
 ],
  "status": {
    "code": ReturnCode,
    "message": "ReturnMessage."
  }
}

The details of the parameters are provided in the following list:

mmDiagIohistParams
An array of all the parameters used for the waiter threads.
"bufType":Buffer type"
The type of buffer cache from which data is retrieved.
"context":"I/O context"
The I/O context that started this I/O.
"devName":"Device name"
The name of the device where the I/O operation is completed.
"disk": "Disk number"
The sequence number of disk in use.
"info1":"Additional information"
Additional information columns based on the buffer type.
"info2":"Additional information"
Additional information columns based on the buffer type.
"ioStartHour":"Time"
The I/O start time in hours.
"ioStartMin":"Time"
The I/O start time in minutes.
"ioStartSec": "Time"
The I/O start time in seconds.
"ioTimeMS": "Time"
The I/O start time in millisecond.
"ioType":"I/O request type."
The type of I/O request.
"nsdNode":"Node name"
The NSD node from which the request is sent.
rw":"R | W"
Specifies whether the I/O process reads or writes the data.
"sectorNum":"Sector number"
The sector number.
"thread":"Thread name"
The name of the thread that started this I/O.

Examples

The following example lists the I/O history details with verbose set to true

Request data:
curl -k -u user:password -X GET --header 'accept:application/json' --header 'Authorization: Basic YWRtaW46YWRtaW4wMDE=' 'https://198.51.100.1:443/scalemgmt/v2/nodes/accesss-41/info/iohist?verbose=true
Response data:
Note: In the JSON data that is returned, the return code indicates whether the command is successful. The response code 200 indicates that the command successfully retrieved the information. Error code 400 represents an invalid request and 500 represents internal server error. 
{
         "mmDiagIohistParams" : [
         {
            "bufType": "LLData",
            "comment": "",
            "context": "Unknown",
            "devName": "vdb",
            "disk": 1,
            "diskUID0": "3364000A",
            "diskUID1": "61727579",
            "info1": "39",
            "info2": "0",
            "ioStartHour": 13,
            "ioStartMin": 53,
            "ioStartSec": 22.041737,
            "ioTimeMS": 13.857,
            "ioType": "lcl",
            "nsdNode": "",
            "rw": "R",
            "sectorNum": 9224192,
            "thread": "TSPcacheCmdThread"

    }
    ],
    "status": {
        "code": 200,
        "message": "The request finished successfully."
    }
}