[SPDK] Re: RPC commands to get log data from NVMe bdevs?

* [SPDK] Re: RPC commands to get log data from NVMe bdevs?
@ 2019-12-03 15:57 Harris, James R
  0 siblings, 0 replies; 2+ messages in thread
From: Harris, James R @ 2019-12-03 15:57 UTC (permalink / raw)
  To: spdk

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Hi Marjorie,

Would it be possible to use the existing bdev_nvme_send_cmd RPC?  And then have a separate Python script (for example, nvme_log_page.py) that:

1) translates the user's command line options to bdev_nvme_send_cmd RPC, and
2) decodes the response into human readable format (or even JSON format) based on the log page requested

My main concern with adding these RPCs to upstream is that it would encourage extending the RPC interface for other types of NVMe commands and other types of NVMe log pages.  My preference has been to try to keep the SPDK JSON-RPC minimal, and build customizations into the client applications instead.

I do understand that some of this may be implemented more easily in C and through an explicit RPC for each log page, since the C data structure for each log page is already defined.  I haven't looked at what it might look like to decode the base64 string into the individual log page fields.  But if we had that infrastructure in place, then this could be extended to new command types and new log page types with "only" some Python code and no changes to the SPDK application itself. 

-Jim

On 12/2/19, 4:57 PM, "Krueger, Marjorie" <marjorie.krueger(a)hpe.com> wrote:

    A few weeks back there was some discussion of a desire to be able to fetch log data from NVMe bdevs, specifically the SMART log page. I have code for a few RPCs ready to push to gerrithub that address that need, just wondering if this is something the SPDK community would like to see?

    Here's the json.md text for the RPCs I have working now:

    ## bdev_nvme_log_get {#rpc_bdev_nvme_log_get}

    Retrieve NVMe bdev log page.

    ### Parameters

    Name                    | Optional | Type        | Description
    ----------------------- | -------- | ----------- | -----------
    bdev_name               | Required | string      | Bdev name
    log_identifier          | Required | number      | NVMe log page identifier
    log_length              | Required | number      | length of log page data to return
    namespace_id            | Optional | number      | Namespace identifier. If not supplied NSID 0xffffffff is used

    ### Result

    Log page result is BASE64 encoded string to be parsed by requester.

    ### Example

    Example request:

    ~~~
    {
      "jsonrpc": "2.0",
      "method": "bdev_nvme_log_get",
      "id": 1,
      "params": {
        "bdev_name": "Nvme1",
        "log_identifier": 2,
        "log_length": 100
      },
    }
    ~~~

    Example response:

    ~~~
    {
      "jsonrpc": "2.0",
      "id": 1,
      "result": [
        {
          "log_page_data": "ACwBZAoAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAwSwAAAAAAAAAAAAAAAAAAA0YCAAAAAAAAAAAAAAAAAGbuBgAAAAAAAAAAAAAAAAA79g0AAAAAAAAAAAAAAAAAAAAAAA=="
        }
      ]
    }
    ~~~
    ## bdev_nvme_smart_log_get {#rpc_bdev_nvme_smart_log_get}

    Retrieve NVMe bdev SMART log page.

    ### Parameters

    Name                    | Optional | Type        | Description
    ----------------------- | -------- | ----------- | -----------
    bdev_name               | Required | string      | Bdev name
    namespace_id            | Optional | number      | Namespace identifier. If not supplied NSID 0xffffffff is used.

    ### Result

    Log page result.

    ### Example

    Example request:

    ~~~
    {
      "jsonrpc": "2.0",
      "method": "bdev_nvme_smart_log_get",
      "id": 1,
      "params": {
        "bdev_name": "Nvme1"
      },
    }
    ~~~

    Example response:

    ~~~
    {
      "jsonrpc": "2.0",
      "id": 1,
      "result": [
        {
            "critical_warning" : 0,
            "temperature" : 299,
            "avail_spare" : 100,
            "spare_thresh" : 10,
            "percent_used" : 0,
            "data_units_read" : 59692,
            "data_units_written" : 1,
            "host_read_commands" : 7402715,
            "host_write_commands" : 4,
            "controller_busy_time" : 0,
            "power_cycles" : 59,
            "power_on_hours" : 821,
            "unsafe_shutdowns" : 33,
            "media_errors" : 0,
            "num_err_log_entries" : 0,
            "warning_temp_time" : 0,
            "critical_comp_time" : 0,
            "temperature_sensor_1" : 299,
            "temperature_sensor_2" : 299,
            "temperature_sensor_3" : 293,
            "thm_temp1_trans_count" : 0,
            "thm_temp2_trans_count" : 0,
            "thm_temp1_total_time" : 0,
            "thm_temp2_total_time" : 0
        }
      ]
    }

    Regards,
    Marjorie

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