mirror of
https://github.com/ceph/ceph
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9dd16638ea
also link to monitoring, as diskprediction cannot function without enabling monitoring. Signed-off-by: Kefu Chai <kchai@redhat.com>
157 lines
4.6 KiB
ReStructuredText
157 lines
4.6 KiB
ReStructuredText
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.. _devices:
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Device Management
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=================
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Ceph tracks which hardware storage devices (e.g., HDDs, SSDs) are consumed by
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which daemons, and collects health metrics about those devices in order to
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provide tools to predict and/or automatically respond to hardware failure.
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Device tracking
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---------------
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You can query which storage devices are in use with::
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ceph device ls
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You can also list devices by daemon or by host::
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ceph device ls-by-daemon <daemon>
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ceph device ls-by-host <host>
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For any individual device, you can query information about its
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location and how it is being consumed with::
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ceph device info <devid>
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Identifying physical devices
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----------------------------
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You can blink the drive LEDs on hardware enclosures to make the replacement of
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failed disks easy and less error-prone. Use the following command::
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device light on|off <devid> [ident|fault] [--force]
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The ``<devid>`` parameter is the device identification. You can obtain this
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information using the following command::
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ceph device ls
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The ``[ident|fault]`` parameter is used to set the kind of light to blink.
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By default, the `identification` light is used.
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.. note::
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This command needs the Cephadm or the Rook `orchestrator <https://docs.ceph.com/docs/master/mgr/orchestrator/#orchestrator-cli-module>`_ module enabled.
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The orchestrator module enabled is shown by executing the following command::
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ceph orch status
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.. _enabling-monitoring:
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Enabling monitoring
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-------------------
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Ceph can also monitor health metrics associated with your device. For
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example, SATA hard disks implement a standard called SMART that
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provides a wide range of internal metrics about the device's usage and
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health, like the number of hours powered on, number of power cycles,
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or unrecoverable read errors. Other device types like SAS and NVMe
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implement a similar set of metrics (via slightly different standards).
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All of these can be collected by Ceph via the ``smartctl`` tool.
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You can enable or disable health monitoring with::
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ceph device monitoring on
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or::
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ceph device monitoring off
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Scraping
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--------
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If monitoring is enabled, metrics will automatically be scraped at regular intervals. That interval can be configured with::
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ceph config set mgr mgr/devicehealth/scrape_frequency <seconds>
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The default is to scrape once every 24 hours.
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You can manually trigger a scrape of all devices with::
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ceph device scrape-health-metrics
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A single device can be scraped with::
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ceph device scrape-health-metrics <device-id>
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Or a single daemon's devices can be scraped with::
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ceph device scrape-daemon-health-metrics <who>
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The stored health metrics for a device can be retrieved (optionally
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for a specific timestamp) with::
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ceph device get-health-metrics <devid> [sample-timestamp]
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Failure prediction
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------------------
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Ceph can predict life expectancy and device failures based on the
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health metrics it collects. There are three modes:
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* *none*: disable device failure prediction.
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* *local*: use a pre-trained prediction model from the ceph-mgr daemon
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The prediction mode can be configured with::
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ceph config set global device_failure_prediction_mode <mode>
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Prediction normally runs in the background on a periodic basis, so it
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may take some time before life expectancy values are populated. You
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can see the life expectancy of all devices in output from::
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ceph device ls
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You can also query the metadata for a specific device with::
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ceph device info <devid>
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You can explicitly force prediction of a device's life expectancy with::
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ceph device predict-life-expectancy <devid>
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If you are not using Ceph's internal device failure prediction but
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have some external source of information about device failures, you
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can inform Ceph of a device's life expectancy with::
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ceph device set-life-expectancy <devid> <from> [<to>]
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Life expectancies are expressed as a time interval so that
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uncertainty can be expressed in the form of a wide interval. The
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interval end can also be left unspecified.
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Health alerts
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-------------
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The ``mgr/devicehealth/warn_threshold`` controls how soon an expected
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device failure must be before we generate a health warning.
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The stored life expectancy of all devices can be checked, and any
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appropriate health alerts generated, with::
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ceph device check-health
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Automatic Mitigation
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--------------------
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If the ``mgr/devicehealth/self_heal`` option is enabled (it is by
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default), then for devices that are expected to fail soon the module
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will automatically migrate data away from them by marking the devices
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"out".
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The ``mgr/devicehealth/mark_out_threshold`` controls how soon an
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expected device failure must be before we automatically mark an osd
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"out".
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