scrutiny/docs/TROUBLESHOOTING_DEVICE_COLLECTOR.md

# Scrutiny <-> SmartMonTools 

Scrutiny uses `smartctl --scan` to detect devices/drives. If your devices are not being detected by Scrutiny, or some 
data is missing, this is probably due to a `smartctl` issue. 
The following page will document commonly asked questions and troubleshooting steps for the Scrutiny S.M.A.R.T. data collector.

## WWN vs Device name
As discussed in [`#117`](https://github.com/AnalogJ/scrutiny/issues/117), `/dev/sd*` device paths are ephemeral. 

> Device paths in Linux aren't guaranteed to be consistent across restarts. Device names consist of major numbers (letters) and minor numbers. When the Linux storage device driver detects a new device, the driver assigns major and minor numbers from the available range to the device. When a device is removed, the device numbers are freed for reuse.
>
> The problem occurs because device scanning in Linux is scheduled by the SCSI subsystem to happen asynchronously. As a result, a device path name can vary across restarts.
>
> https://docs.microsoft.com/en-us/troubleshoot/azure/virtual-machines/troubleshoot-device-names-problems

While the Docker Scrutiny collector does require devices to attached to the docker container by device name (using `--device=/dev/sd..`), internally 
Scrutiny stores and references the devices by their `WWN` which is globally unique, and never changes. 

As such, passing devices to the Scrutiny collector container using `/dev/disk/by-id/`, `/dev/disk/by-label/`, `/dev/disk/by-path/` and `/dev/disk/by-uuid/`
paths are unnecessary, unless you'd like to ensure the docker run command never needs to change.


## Device Detection By Smartctl

The first thing you'll want to do is run `smartctl` locally (not in Docker) and make sure the output shows all your drives as expected.
See the `Drive Types` section below for what this output should look like for `NVMe`/`ATA`/`RAID` drives.

```bash
smartctl --scan

/dev/sda -d scsi # /dev/sda, SCSI device
/dev/sdb -d scsi # /dev/sdb, SCSI device
/dev/sdc -d scsi # /dev/sdc, SCSI device
/dev/sdd -d scsi # /dev/sdd, SCSI device
```

Once you've verified that `smartctl` correctly detects your drives, make sure scrutiny is correctly detecting them as well.
> NOTE: make sure you specify all the devices you'd like scrutiny to process using `--device=` flags.

```bash
docker run -it --rm \
  -v /run/udev:/run/udev:ro \
  --cap-add SYS_RAWIO \
  --device=/dev/sda \
  --device=/dev/sdb \
  ghcr.io/analogj/scrutiny:master-collector smartctl --scan
```

If the output is the same, your devices will be processed by Scrutiny.

### Collector Config File
In some cases `--scan` does not correctly detect the device type, returning [incomplete SMART data](https://github.com/AnalogJ/scrutiny/issues/45).
Scrutiny will supports overriding the detected device type via the config file.

### RAID Controllers (Megaraid/3ware/HBA/Adaptec/HPE/etc)
Smartctl has support for a large number of [RAID controllers](https://www.smartmontools.org/wiki/Supported_RAID-Controllers), however this 
support is not automatic, and may require some additional device type hinting. You can provide this information to the Scrutiny collector
using a collector config file. See [example.collector.yaml](/example.collector.yaml)

> NOTE: If you use docker, you **must** pass though the RAID virtual disk to the container using `--device` (see below)
>
> This device may be in `/dev/*` or `/dev/bus/*`. 
>
> If you're unsure, run `smartctl --scan` on your host, and pass all listed devices to the container.

```yaml
# /scrutiny/config/collector.yaml
devices:
  # Dell PERC/Broadcom Megaraid example: https://github.com/AnalogJ/scrutiny/issues/30
  - device: /dev/bus/0
    type:
      - megaraid,14
      - megaraid,15
      - megaraid,18
      - megaraid,19
      - megaraid,20
      - megaraid,21

  - device: /dev/twa0
    type:
      - 3ware,0
      - 3ware,1
      - 3ware,2
      - 3ware,3
      - 3ware,4
      - 3ware,5
  
  # Adapec RAID: https://github.com/AnalogJ/scrutiny/issues/189
  - device: /dev/sdb
    type:
      - aacraid,0,0,0
      - aacraid,0,0,1
  
  # HPE Smart Array example:  https://github.com/AnalogJ/scrutiny/issues/213
  - device: /dev/sda
    type:
      - 'cciss,0'
      - 'cciss,1'
```

### NVMe Drives
As mentioned in the [README.md](/README.md), NVMe devices require both `--cap-add SYS_RAWIO` and `--cap-add SYS_ADMIN` 
to allow smartctl permission to query your NVMe device SMART data [#26](https://github.com/AnalogJ/scrutiny/issues/26)

When attaching NVMe devices using `--device=/dev/nvme..`, make sure to provide the device controller (`/dev/nvme0`) 
instead of the block device (`/dev/nvme0n1`). See [#209](https://github.com/AnalogJ/scrutiny/issues/209).

> The character device /dev/nvme0 is the NVME device controller, and block devices like /dev/nvme0n1 are the NVME storage namespaces: the devices you use for actual storage, which will behave essentially as disks.
>
> In enterprise-grade hardware, there might be support for several namespaces, thin provisioning within namespaces and other features. For now, you could think namespaces as sort of meta-partitions with extra features for enterprise use.

### ATA

### Standby/Sleeping Disks
- https://github.com/AnalogJ/scrutiny/issues/221
- https://github.com/AnalogJ/scrutiny/issues/157

### Volume Mount All Devices (`/dev`) - Privileged


## Hub & Spoke model, with multiple Hosts.

When deploying Scrutiny in a hub & spoke model, it can be difficult to determine exactly which node a set of devices are associated with.
Thankfully the collector has a special `--host-id` flag (or `COLLECTOR_HOST_ID` env variable) that can be used to associate devices with a friendly host name.

See the [docs/INSTALL_HUB_SPOKE.md](/docs/INSTALL_HUB_SPOKE.md) guide for more information.