Metrics for SCSI devices(SMARTCTL PLUGIN) about telegraf HOT 9 CLOSED

After fighting your JSON output from the previous issue I think this is your output:

{
  "json_format_version": [
    1,
    0
  ],
  "smartctl": {
    "version": [
      7,
      4
    ],
    "pre_release": false,
    "svn_revision": "6328",
    "platform_info": "x86_64-linux-4.14.0-1-amd64",
    "build_info": "(local build)",
    "argv": [
      "smartctl",
      "--json",
      "--all",
      "/dev/sdaa",
      "--device",
      "scsi"
    ],
    "exit_status": 0
  },
  "local_time": {
    "time_t": 1712853808,
    "asctime": "Thu Apr 11 16:43:28 2024 UTC"
  },
  "device": {
    "name": "/dev/sdaa",
    "info_name": "/dev/sdaa",
    "type": "scsi",
    "protocol": "SCSI"
  },
  "scsi_vendor": "XYZZZZZZ",
  "scsi_product": "ST100000000",
  "scsi_model_name": "SEAGATE ST0000000",
  "scsi_revision": "RSL5",
  "scsi_version": "SPC-5",
  "user_capacity": {
    "blocks": 26789019748,
    "bytes": 13715978079776
  },
  "logical_block_size": 512,
  "physical_block_size": 4096,
  "scsi_protection_type": 2,
  "scsi_protection_interval_bytes_per_lb": 8,
  "scsi_lb_provisioning": {
    "name": "fully provisioned",
    "value": 0,
    "management_enabled": {
      "name": "LBPME",
      "value": 0
    },
    "read_zeros": {
      "name": "LBPRZ",
      "value": 0
    }
  },
  "rotation_rate": 7200,
  "form_factor": {
    "scsi_value": 2,
    "name": "3.5 inches"
  },
  "logical_unit_id": "0x5000cb0847",
  "serial_number": "XYZZZZ",
  "device_type": {
    "scsi_terminology": "Peripheral Device Type [PDT]",
    "scsi_value": 0,
    "name": "disk"
  },
  "scsi_transport_protocol": {
    "name": "SAS (SPL-4)",
    "value": 6
  },
  "smart_support": {
    "available": true,
    "enabled": true
  },
  "temperature_warning": {
    "enabled": true
  },
  "smart_status": {
    "passed": true
  },
  "temperature": {
    "current": 24,
    "drive_trip": 60
  },
  "power_on_time": {
    "hours": 34222,
    "minutes": 9
  },
  "scsi_start_stop_cycle_counter": {
    "year_of_manufacture": "2019",
    "week_of_manufacture": "35",
    "specified_cycle_count_over_device_lifetime": 50000,
    "accumulated_start_stop_cycles": 220,
    "specified_load_unload_count_over_device_lifetime": 600000,
    "accumulated_load_unload_cycles": 1606
  },
  "scsi_grown_defect_list": 0,
  "seagate_farm_log": {
    "supported": true
  },
  "scsi_error_counter_log": {
    "read": {
      "errors_corrected_by_eccfast": 0,
      "errors_corrected_by_eccdelayed": 0,
      "errors_corrected_by_rereads_rewrites": 0,
      "total_errors_corrected": 0,
      "correction_algorithm_invocations": 0,
      "gigabytes_processed": "316009.846",
      "total_uncorrected_errors": 0
    },
    "write": {
      "errors_corrected_by_eccfast": 0,
      "errors_corrected_by_eccdelayed": 0,
      "errors_corrected_by_rereads_rewrites": 20,
      "total_errors_corrected": 20,
      "correction_algorithm_invocations": 20,
      "gigabytes_processed": "132824.923",
      "total_uncorrected_errors": 0
    },
    "verify": {
      "errors_corrected_by_eccfast": 0,
      "errors_corrected_by_eccdelayed": 0,
      "errors_corrected_by_rereads_rewrites": 0,
      "total_errors_corrected": 0,
      "correction_algorithm_invocations": 0,
      "gigabytes_processed": "1467.278",
      "total_uncorrected_errors": 0
    }
  },
  "scsi_self_test_0": {
    "code": {
      "value": 2,
      "string": "Background long"
    },
    "result": {
      "value": 0,
      "string": "Completed"
    },
    "power_on_time": {
      "hours": 90,
      "aka": "accumulated_power_on_hours"
    }
  },
  "scsi_self_test_1": {
    "code": {
      "value": 2,
      "string": "Background long"
    },
    "result": {
      "value": 0,
      "string": "Completed"
    },
    "power_on_time": {
      "hours": 66,
      "aka": "accumulated_power_on_hours"
    }
  },
  "scsi_self_test_2": {
    "code": {
      "value": 7,
      "string": "Reserved(7)"
    },
    "result": {
      "value": 0,
      "string": "Completed"
    },
    "failed_segment": {
      "value": 80,
      "aka": "self_test_number"
    },
    "power_on_time": {
      "hours": 5,
      "aka": "accumulated_power_on_hours"
    }
  },
  "scsi_self_test_3": {
    "code": {
      "value": 1,
      "string": "Background short"
    },
    "result": {
      "value": 0,
      "string": "Completed"
    },
    "power_on_time": {
      "hours": 2,
      "aka": "accumulated_power_on_hours"
    }
  },
  "scsi_extended_self_test_seconds": 80400
}

from telegraf.

Most of these seem acceptable, however, I have questions about these two:

form_factor:
scsi_value:

Which comes from:

  "form_factor": {
    "scsi_value": 2,
    "name": "3.5 inches"
  },

Why do you want the value and not the name?

scsi_lb_provisioning

That comes from the following JSON:

  "scsi_lb_provisioning": {
    "name": "fully provisioned",
    "value": 0,
    "management_enabled": {
      "name": "LBPME",
      "value": 0
    },
    "read_zeros": {
      "name": "LBPRZ",
      "value": 0
    }
  },

What information is actually useful?

from telegraf.

Most of these seem acceptable, however, I have questions about these two:

form_factor:
scsi_value:

Which comes from:

  "form_factor": {
    "scsi_value": 2,
    "name": "3.5 inches"
  },

Why do you want the value and not the name?

scsi_lb_provisioning

That comes from the following JSON:

  "scsi_lb_provisioning": {
    "name": "fully provisioned",
    "value": 0,
    "management_enabled": {
      "name": "LBPME",
      "value": 0
    },
    "read_zeros": {
      "name": "LBPRZ",
      "value": 0
    }
  },

What information is actually useful?

I want to gather as much information as possible from the SCSI devices, so there is no particular reason in missing "name" "form_factor": {
"scsi_value": 2,
"name": "3.5 inches"
},
and the following json
"scsi_lb_provisioning": {
"name": "fully provisioned",
"value": 0,
"management_enabled": {
"name": "LBPME",
"value": 0
},
"read_zeros": {
"name": "LBPRZ",
"value": 0
}
},
If these information also available that would be much appreciated. thank you.

from telegraf.

I want to gather as much information as possible from the SCSI devices, so there is no particular reason in missing "name"

What is your output?

The goal of the plugin is not to capture every bit of information or field, but instead the valuable metrics.

from telegraf.

I want to gather as much information as possible from the SCSI devices, so there is no particular reason in missing "name"

What is your output?

The goal of the plugin is not to capture every bit of information or field, but instead the valuable metrics.

@powersj My intension is to collect as much available information as possible from SCSI devices, to understand the behavior of the devices based on these information (metrices) on drives failure.

from telegraf.

And if you aren't going to answer my questions shall I close this?

What is your output?

from telegraf.

{
  "json_format_version": [
    1,
    0
  ],
  "smartctl": {
    "version": [
      7,
      4
    ],
    "pre_release": false,
    "svn_revision": "6328",
    "platform_info": "x86_64-linux-4.14.0-1-amd64",
    "build_info": "(local build)",
    "argv": [
      "smartctl",
      "--json",
      "--all",
      "/dev/sdaa",
      "--device",
      "scsi"
    ],
    "exit_status": 0
  },
  "local_time": {
    "time_t": 1712853808,
    "asctime": "Thu Apr 11 16:43:28 2024 UTC"
  },
  "device": {
    "name": "/dev/sdaa",
    "info_name": "/dev/sdaa",
    "type": "scsi",
    "protocol": "SCSI"
  },
  "scsi_vendor": "XYZZZZZZ",
  "scsi_product": "ST100000000",
  "scsi_model_name": "SEAGATE ST0000000",
  "scsi_revision": "RSL5",
  "scsi_version": "SPC-5",
  "user_capacity": {
    "blocks": 26789019748,
    "bytes": 13715978079776
  },
  "logical_block_size": 512,
  "physical_block_size": 4096,
  "scsi_protection_type": 2,
  "scsi_protection_interval_bytes_per_lb": 8,
  "scsi_lb_provisioning": {
    "name": "fully provisioned",
    "value": 0,
    "management_enabled": {
      "name": "LBPME",
      "value": 0
    },
    "read_zeros": {
      "name": "LBPRZ",
      "value": 0
    }
  },
  "rotation_rate": 7200,
  "form_factor": {
    "scsi_value": 2,
    "name": "3.5 inches"
  },
  "logical_unit_id": "0x5000cb0847",
  "serial_number": "XYZZZZ",
  "device_type": {
    "scsi_terminology": "Peripheral Device Type [PDT]",
    "scsi_value": 0,
    "name": "disk"
  },
  "scsi_transport_protocol": {
    "name": "SAS (SPL-4)",
    "value": 6
  },
  "smart_support": {
    "available": true,
    "enabled": true
  },
  "temperature_warning": {
    "enabled": true
  },
  "smart_status": {
    "passed": true
  },
  "temperature": {
    "current": 24,
    "drive_trip": 60
  },
  "power_on_time": {
    "hours": 34222,
    "minutes": 9
  },
  "scsi_start_stop_cycle_counter": {
    "year_of_manufacture": "2019",
    "week_of_manufacture": "35",
    "specified_cycle_count_over_device_lifetime": 50000,
    "accumulated_start_stop_cycles": 220,
    "specified_load_unload_count_over_device_lifetime": 600000,
    "accumulated_load_unload_cycles": 1606
  },
  "scsi_grown_defect_list": 0,
  "seagate_farm_log": {
    "supported": true
  },
  "scsi_error_counter_log": {
    "read": {
      "errors_corrected_by_eccfast": 0,
      "errors_corrected_by_eccdelayed": 0,
      "errors_corrected_by_rereads_rewrites": 0,
      "total_errors_corrected": 0,
      "correction_algorithm_invocations": 0,
      "gigabytes_processed": "316009.846",
      "total_uncorrected_errors": 0
    },
    "write": {
      "errors_corrected_by_eccfast": 0,
      "errors_corrected_by_eccdelayed": 0,
      "errors_corrected_by_rereads_rewrites": 20,
      "total_errors_corrected": 20,
      "correction_algorithm_invocations": 20,
      "gigabytes_processed": "132824.923",
      "total_uncorrected_errors": 0
    },
    "verify": {
      "errors_corrected_by_eccfast": 0,
      "errors_corrected_by_eccdelayed": 0,
      "errors_corrected_by_rereads_rewrites": 0,
      "total_errors_corrected": 0,
      "correction_algorithm_invocations": 0,
      "gigabytes_processed": "1467.278",
      "total_uncorrected_errors": 0
    }
  },
  "scsi_self_test_0": {
    "code": {
      "value": 2,
      "string": "Background long"
    },
    "result": {
      "value": 0,
      "string": "Completed"
    },
    "power_on_time": {
      "hours": 90,
      "aka": "accumulated_power_on_hours"
    }
  },
  "scsi_self_test_1": {
    "code": {
      "value": 2,
      "string": "Background long"
    },
    "result": {
      "value": 0,
      "string": "Completed"
    },
    "power_on_time": {
      "hours": 66,
      "aka": "accumulated_power_on_hours"
    }
  },
  "scsi_self_test_2": {
    "code": {
      "value": 7,
      "string": "Reserved(7)"
    },
    "result": {
      "value": 0,
      "string": "Completed"
    },
    "failed_segment": {
      "value": 80,
      "aka": "self_test_number"
    },
    "power_on_time": {
      "hours": 5,
      "aka": "accumulated_power_on_hours"
    }
  },
  "scsi_self_test_3": {
    "code": {
      "value": 1,
      "string": "Background short"
    },
    "result": {
      "value": 0,
      "string": "Completed"
    },
    "power_on_time": {
      "hours": 2,
      "aka": "accumulated_power_on_hours"
    }
  },
  "scsi_extended_self_test_seconds": 80400
}

my output:
{
"json_format_version": [
1,
0
],
"smartctl": {
"version": [
7,
4
],
"pre_release": false,
"svn_revision": "6328",
"platform_info": "x86_64-linux-4.14.0-1-amd64",
"build_info": "(local build)",
"argv": [
"smartctl",
"--json",
"--all",
"/dev/sdaa",
"--device",
"scsi"
],
"exit_status": 0
},
"local_time": {
"time_t": 1712853808,
"asctime": "Thu Apr 11 16:43:28 2024 UTC"
},
"device": {
"name": "/dev/sdaa",
"info_name": "/dev/sdaa",
"type": "scsi",
"protocol": "SCSI"
},
"scsi_vendor": "XYZZZZZZ",
"scsi_product": "ST100000000",
"scsi_model_name": "SEAGATE ST0000000",
"scsi_revision": "RSL5",
"scsi_version": "SPC-5",
"user_capacity": {
"blocks": 26789019748,
"bytes": 13715978079776
},
"logical_block_size": 512,
"physical_block_size": 4096,
"scsi_protection_type": 2,
"scsi_protection_interval_bytes_per_lb": 8,
"scsi_lb_provisioning": {
"name": "fully provisioned",
"value": 0,
"management_enabled": {
"name": "LBPME",
"value": 0
},
"read_zeros": {
"name": "LBPRZ",
"value": 0
}
},
"rotation_rate": 7200,
"form_factor": {
"scsi_value": 2,
"name": "3.5 inches"
},
"logical_unit_id": "0x5000cb0847",
"serial_number": "XYZZZZ",
"device_type": {
"scsi_terminology": "Peripheral Device Type [PDT]",
"scsi_value": 0,
"name": "disk"
},
"scsi_transport_protocol": {
"name": "SAS (SPL-4)",
"value": 6
},
"smart_support": {
"available": true,
"enabled": true
},
"temperature_warning": {
"enabled": true
},
"smart_status": {
"passed": true
},
"temperature": {
"current": 24,
"drive_trip": 60
},
"power_on_time": {
"hours": 34222,
"minutes": 9
},
"scsi_start_stop_cycle_counter": {
"year_of_manufacture": "2019",
"week_of_manufacture": "35",
"specified_cycle_count_over_device_lifetime": 50000,
"accumulated_start_stop_cycles": 220,
"specified_load_unload_count_over_device_lifetime": 600000,
"accumulated_load_unload_cycles": 1606
},
"scsi_grown_defect_list": 0,
"seagate_farm_log": {
"supported": true
},
"scsi_error_counter_log": {
"read": {
"errors_corrected_by_eccfast": 0,
"errors_corrected_by_eccdelayed": 0,
"errors_corrected_by_rereads_rewrites": 0,
"total_errors_corrected": 0,
"correction_algorithm_invocations": 0,
"gigabytes_processed": "316009.846",
"total_uncorrected_errors": 0
},
"write": {
"errors_corrected_by_eccfast": 0,
"errors_corrected_by_eccdelayed": 0,
"errors_corrected_by_rereads_rewrites": 20,
"total_errors_corrected": 20,
"correction_algorithm_invocations": 20,
"gigabytes_processed": "132824.923",
"total_uncorrected_errors": 0
},
"verify": {
"errors_corrected_by_eccfast": 0,
"errors_corrected_by_eccdelayed": 0,
"errors_corrected_by_rereads_rewrites": 0,
"total_errors_corrected": 0,
"correction_algorithm_invocations": 0,
"gigabytes_processed": "1467.278",
"total_uncorrected_errors": 0
}
},
"scsi_self_test_0": {
"code": {
"value": 2,
"string": "Background long"
},
"result": {
"value": 0,
"string": "Completed"
},
"power_on_time": {
"hours": 90,
"aka": "accumulated_power_on_hours"
}
},
"scsi_self_test_1": {
"code": {
"value": 2,
"string": "Background long"
},
"result": {
"value": 0,
"string": "Completed"
},
"power_on_time": {
"hours": 66,
"aka": "accumulated_power_on_hours"
}
},
"scsi_self_test_2": {
"code": {
"value": 7,
"string": "Reserved(7)"
},
"result": {
"value": 0,
"string": "Completed"
},
"failed_segment": {
"value": 80,
"aka": "self_test_number"
},
"power_on_time": {
"hours": 5,
"aka": "accumulated_power_on_hours"
}
},
"scsi_self_test_3": {
"code": {
"value": 1,
"string": "Background short"
},
"result": {
"value": 0,
"string": "Completed"
},
"power_on_time": {
"hours": 2,
"aka": "accumulated_power_on_hours"
}
},
"scsi_extended_self_test_seconds": 80400
}

from telegraf.

my output:

ok maybe my bad as there is a misunderstanding here. I am trying to understand what you are outputting the collected metrics to. As in, what your telegraf output is.

from telegraf.

my output:

ok maybe my bad as there is a misunderstanding here. I am trying to understand what you are outputting the collected metrics to. As in, what your telegraf output is.

@powersj this is my telegraf output:
smartctl,host=host-XYZ,name=/dev/sdb,serial=ZZZXXX,type=scsi,user=root capacity=13715978059776i,health_ok=true,temperature=24i,firmware="" 1713231001000000000
smartctl_scsi_error_counter_log,host=host-XYZ,name=/dev/sdb,page=read,serial=XXXXXXXX,type=scsi,user=root total_errors_corrected=1i,correction_algorithm_invocations=1i,gigabytes_processed="304506.635",total_uncorrected_errors=0i,errors_corrected_by_eccfast=0i,errors_corrected_by_eccdelayed=1i,errors_corrected_by_rereads_rewrites=0i 1713231001000000000
smartctl_scsi_error_counter_log,host=host-XYZ,name=/dev/sdb,page=write,serial=XXXXXXXX,type=scsi,user=root total_uncorrected_errors=0i,errors_corrected_by_eccfast=0i,errors_corrected_by_eccdelayed=0i,errors_corrected_by_rereads_rewrites=10i,total_errors_corrected=10i,correction_algorithm_invocations=10i,gigabytes_processed="130090.017" 1713231001000000000
smartctl_scsi_error_counter_log,host=host-XYZ,name=/dev/sdb,page=verify,serial=XXXXXXXX,type=scsi,user=root total_errors_corrected=1i,correction_algorithm_invocations=1i,gigabytes_processed="1499.323",total_uncorrected_errors=0i,errors_corrected_by_eccfast=0i,errors_corrected_by_eccdelayed=1i,errors_corrected_by_rereads_rewrites=0i 1713231001000000000
smartctl,host=host-XYZ,name=/dev/sdc,serial=YYYYYYYY,type=scsi,user=root capacity=13715978059776i,health_ok=true,temperature=31i,firmware="" 1713231002000000000
smartctl_scsi_error_counter_log,host=host-XYZ,name=/dev/sdc,page=read,serial=YYYYYYYY,type=scsi,user=root errors_corrected_by_eccfast=0i,errors_corrected_by_eccdelayed=0i,errors_corrected_by_rereads_rewrites=0i,total_errors_corrected=0i,correction_algorithm_invocations=0i,gigabytes_processed="62816.200",total_uncorrected_errors=0i 1713231002000000000
smartctl_scsi_error_counter_log,host=host-XYZ,name=/dev/sdc,page=write,serial=YYYYYYYY,type=scsi,user=root correction_algorithm_invocations=0i,gigabytes_processed="24493.910",total_uncorrected_errors=0i,errors_corrected_by_eccfast=0i,errors_corrected_by_eccdelayed=0i,errors_corrected_by_rereads_rewrites=0i,total_errors_corrected=0i 1713231002000000000
smartctl_scsi_error_counter_log,host=host-XYZ,name=/dev/sdc,page=verify,serial=YYYYYYYY,type=scsi,user=root total_uncorrected_errors=0i,errors_corrected_by_eccfast=0i,errors_corrected_by_eccdelayed=0i,errors_corrected_by_rereads_rewrites=0i,total_errors_corrected=0i,correction_algorithm_invocations=0i,gigabytes_processed="" 1713231002000000000
smartctl,host=host-XYZ,name=/dev/sdd,serial=ZZZZZZ,type=scsi,user=root capacity=13715978059776i,health_ok=true,temperature=31i,firmware="" 1713231003000000000
smartctl_scsi_error_counter_log,host=host-XYZ,name=/dev/sdd,page=read,serial=ZZZZZZ,type=scsi,user=root errors_corrected_by_eccfast=0i,errors_corrected_by_eccdelayed=0i,errors_corrected_by_rereads_rewrites=0i,total_errors_corrected=0i,correction_algorithm_invocations=0i,gigabytes_processed="113047.357",total_uncorrected_errors=0i 1713231003000000000
smartctl_scsi_error_counter_log,host=host-XYZ,name=/dev/sdd,page=write,serial=ZZZZZZ,type=scsi,user=root gigabytes_processed="28932.558",total_uncorrected_errors=0i,errors_corrected_by_eccfast=0i,errors_corrected_by_eccdelayed=0i,errors_corrected_by_rereads_rewrites=0i,total_errors_corrected=0i,correction_algorithm_invocations=0i 1713231003000000000
smartctl_scsi_error_counter_log,host=host-XYZ,name=/dev/sdd,page=verify,serial=ZZZZZZ,type=scsi,user=root errors_corrected_by_rereads_rewrites=0i,total_errors_corrected=0i,correction_algorithm_invocations=0i,gigabytes_processed="89.801",total_uncorrected_errors=0i,errors_corrected_by_eccfast=0i,errors_corrected_by_eccdelayed=0i 1713231003000000000
smartctl,host=host-XYZ,name=/dev/sde,serial=WWWWWWWW,type=scsi,user=root health_ok=true,temperature=30i,firmware="",capacity=13715978059776i 1713231004000000000
smartctl_scsi_error_counter_log,host=host-XYZ,name=/dev/sde,page=read,serial=WWWWWWWW,type=scsi,user=root errors_corrected_by_eccfast=0i,errors_corrected_by_eccdelayed=1i,errors_corrected_by_rereads_rewrites=0i,total_errors_corrected=1i,correction_algorithm_invocations=2i,gigabytes_processed="325778.017",total_uncorrected_errors=0i 1713231004000000000
smartctl_scsi_error_counter_log,host=host-XYZ,name=/dev/sde,page=write,serial=WWWWWWWW,type=scsi,user=root errors_corrected_by_eccfast=0i,errors_corrected_by_eccdelayed=0i,errors_corrected_by_rereads_rewrites=52i,total_errors_corrected=52i,correction_algorithm_invocations=52i,gigabytes_processed="134566.270",total_uncorrected_errors=0i 1713231004000000000
smartctl_scsi_error_counter_log,host=host-XYZ,name=/dev/sde,page=verify,serial=WWWWWWWW,type=scsi,user=root gigabytes_processed="1489.131",total_uncorrected_errors=0i,errors_corrected_by_eccfast=0i,errors_corrected_by_eccdelayed=3i,errors_corrected_by_rereads_rewrites=0i,total_errors_corrected=3i,correction_algorithm_invocations=3i 1713231004000000000
smartctl,host=host-XYZ,name=/dev/sdf,serial=UUUUUUUU,type=scsi,user=root health_ok=true,temperature=28i,firmware="",capacity=13715978059776i 1713231005000000000
smartctl_scsi_error_counter_log,host=host-XYZ,name=/dev/sdf,page=read,serial=UUUUUUUU,type=scsi,user=root gigabytes_processed="369626.386",total_uncorrected_errors=0i,errors_corrected_by_eccfast=0i,errors_corrected_by_eccdelayed=17i,errors_corrected_by_rereads_rewrites=0i,total_errors_corrected=17i,correction_algorithm_invocations=17i 1713231005000000000
smartctl_scsi_error_counter_log,host=host-XYZ,name=/dev/sdf,page=write,serial=UUUUUUUU,type=scsi,user=root total_errors_corrected=458i,correction_algorithm_invocations=458i,gigabytes_processed="132414.073",total_uncorrected_errors=0i,errors_corrected_by_eccfast=0i,errors_corrected_by_eccdelayed=0i,errors_corrected_by_rereads_rewrites=458i 1713231005000000000
smartctl_scsi_error_counter_log,host=host-XYZ,name=/dev/sdf,page=verify,serial=UUUUUUUU,type=scsi,user=root total_uncorrected_errors=0i,errors_corrected_by_eccfast=0i,errors_corrected_by_eccdelayed=15i,errors_corrected_by_rereads_rewrites=0i,total_errors_corrected=15i,correction_algorithm_invocations=15i,gigabytes_processed="1492.004" 1713231005000000000

from telegraf.