The WolfspyreLabs Blog/ 2023/ Posts from January/ Maintenance and Monitoring/ Maintenance and Monitoring Back to the top… Testing (( You are Here )) Reading and References Maintenance #https://docs.ceph.com/en/latest/rados/operations/health-checks/ https://sabaini.at/pages/ceph-cheatsheet.html ============= Health checks #Overview #There is a finite set of possible health messages that a Ceph cluster can raise – these are defined as health checks which have unique identifiers. The identifier is a terse pseudo-human-readable (i.e. like a variable name) string. It is intended to enable tools (such as UIs) to make sense of health checks, and present them in a way that reflects their meaning. This page lists the health checks that are raised by the monitor and manager daemons. In addition to these, you may also see health checks that originate from MDS daemons (see :ref:cephfs-health-messages), and health checks that are defined by ceph-mgr python modules. Definitions #Monitor #DAEMON_OLD_VERSION Warn if old version(s) of Ceph are running on any daemons. It will generate a health error if multiple versions are detected. This condition must exist for over mon_warn_older_version_delay (set to 1 week by default) in order for the health condition to be triggered. This allows most upgrades to proceed without falsely seeing the warning. If upgrade is paused for an extended time period, health mute can be used like this “ceph health mute DAEMON_OLD_VERSION –sticky”. In this case after upgrade has finished use “ceph health unmute DAEMON_OLD_VERSION”. MON_DOWN One or more monitor daemons is currently down. The cluster requires a majority (more than 1/2) of the monitors in order to function. When one or more monitors are down, clients may have a harder time forming their initial connection to the cluster as they may need to try more addresses before they reach an operating monitor. The down monitor daemon should generally be restarted as soon as possible to reduce the risk of a subsequent monitor failure leading to a service outage. MON_CLOCK_SKEW The clocks on the hosts running the ceph-mon monitor daemons are not sufficiently well synchronized. This health alert is raised if the cluster detects a clock skew greater than mon_clock_drift_allowed. This is best resolved by synchronizing the clocks using a tool like ntpd or chrony. If it is impractical to keep the clocks closely synchronized, the mon_clock_drift_allowed threshold can also be increased, but this value must stay significantly below the mon_lease interval in order for monitor cluster to function properly. MON_MSGR2_NOT_ENABLED The :confval:ms_bind_msgr2 option is enabled but one or more monitors is not configured to bind to a v2 port in the cluster’s monmap. This means that features specific to the msgr2 protocol (e.g., encryption) are not available on some or all connections. In most cases this can be corrected by issuing the command: .. prompt:: bash $ ceph mon enable-msgr2 That command will change any monitor configured for the old default port 6789 to continue to listen for v1 connections on 6789 and also listen for v2 connections on the new default 3300 port. If a monitor is configured to listen for v1 connections on a non-standard port (not 6789), then the monmap will need to be modified manually. MON_DISK_LOW One or more monitors is low on disk space. This alert triggers if the available space on the file system storing the monitor database (normally /var/lib/ceph/mon), as a percentage, drops below mon_data_avail_warn (default: 30%). This may indicate that some other process or user on the system is filling up the same file system used by the monitor. It may also indicate that the monitors database is large (see MON_DISK_BIG below). If space cannot be freed, the monitor’s data directory may need to be moved to another storage device or file system (while the monitor daemon is not running, of course). MON_DISK_CRIT One or more monitors is critically low on disk space. This alert triggers if the available space on the file system storing the monitor database (normally /var/lib/ceph/mon), as a percentage, drops below mon_data_avail_crit (default: 5%). See MON_DISK_LOW, above. MON_DISK_BIG The database size for one or more monitors is very large. This alert triggers if the size of the monitor’s database is larger than mon_data_size_warn (default: 15 GiB). A large database is unusual, but may not necessarily indicate a problem. Monitor databases may grow in size when there are placement groups that have not reached an active+clean state in a long time. This may also indicate that the monitor’s database is not properly compacting, which has been observed with some older versions of leveldb and rocksdb. Forcing a compaction with ceph daemon mon.<id> compact may shrink the on-disk size. This warning may also indicate that the monitor has a bug that is preventing it from pruning the cluster metadata it stores. If the problem persists, please report a bug. The warning threshold may be adjusted with: .. prompt:: bash $ ceph config set global mon_data_size_warn AUTH_INSECURE_GLOBAL_ID_RECLAIM _______________________________ One or more clients or daemons are connected to the cluster that are not securely reclaiming their global_id (a unique number identifying each entity in the cluster) when reconnecting to a monitor. The client is being permitted to connect anyway because the ``auth_allow_insecure_global_id_reclaim`` option is set to true (which may be necessary until all ceph clients have been upgraded), and the ``auth_expose_insecure_global_id_reclaim`` option set to ``true`` (which allows monitors to detect clients with insecure reclaim early by forcing them to reconnect right after they first authenticate). You can identify which client(s) are using unpatched ceph client code with: .. prompt:: bash $ ceph health detail Clients' global_id reclaim behavior can also seen in the ``global_id_status`` field in the dump of clients connected to an individual monitor (``reclaim_insecure`` means the client is unpatched and is contributing to this health alert): .. prompt:: bash $ ceph tell mon.\* sessions We strongly recommend that all clients in the system are upgraded to a newer version of Ceph that correctly reclaims global_id values. Once all clients have been updated, you can stop allowing insecure reconnections with: .. prompt:: bash $ ceph config set mon auth_allow_insecure_global_id_reclaim false If it is impractical to upgrade all clients immediately, you can silence this warning temporarily with: .. prompt:: bash $ ceph health mute AUTH_INSECURE_GLOBAL_ID_RECLAIM 1w # 1 week Although we do NOT recommend doing so, you can also disable this warning indefinitely with: .. prompt:: bash $ ceph config set mon mon_warn_on_insecure_global_id_reclaim false AUTH_INSECURE_GLOBAL_ID_RECLAIM_ALLOWED _______________________________________ Ceph is currently configured to allow clients to reconnect to monitors using an insecure process to reclaim their previous global_id because the setting ``auth_allow_insecure_global_id_reclaim`` is set to ``true``. It may be necessary to leave this setting enabled while existing Ceph clients are upgraded to newer versions of Ceph that correctly and securely reclaim their global_id. If the ``AUTH_INSECURE_GLOBAL_ID_RECLAIM`` health alert has not also been raised and the ``auth_expose_insecure_global_id_reclaim`` setting has not been disabled (it is on by default), then there are currently no clients connected that need to be upgraded, and it is safe to disallow insecure global_id reclaim with: .. prompt:: bash $ ceph config set mon auth_allow_insecure_global_id_reclaim false If there are still clients that need to be upgraded, then this alert can be silenced temporarily with: .. prompt:: bash $ ceph health mute AUTH_INSECURE_GLOBAL_ID_RECLAIM_ALLOWED 1w # 1 week Although we do NOT recommend doing so, you can also disable this warning indefinitely with: .. prompt:: bash $ ceph config set mon mon_warn_on_insecure_global_id_reclaim_allowed false Manager ------- MGR_DOWN ________ All manager daemons are currently down. The cluster should normally have at least one running manager (``ceph-mgr``) daemon. If no manager daemon is running, the cluster's ability to monitor itself will be compromised, and parts of the management API will become unavailable (for example, the dashboard will not work, and most CLI commands that report metrics or runtime state will block). However, the cluster will still be able to perform all IO operations and recover from failures. The down manager daemon should generally be restarted as soon as possible to ensure that the cluster can be monitored (e.g., so that the ``ceph -s`` information is up to date, and/or metrics can be scraped by Prometheus). MGR_MODULE_DEPENDENCY _____________________ An enabled manager module is failing its dependency check. This health check should come with an explanatory message from the module about the problem. For example, a module might report that a required package is not installed: install the required package and restart your manager daemons. This health check is only applied to enabled modules. If a module is not enabled, you can see whether it is reporting dependency issues in the output of `ceph module ls`. MGR_MODULE_ERROR ________________ A manager module has experienced an unexpected error. Typically, this means an unhandled exception was raised from the module's `serve` function. The human readable description of the error may be obscurely worded if the exception did not provide a useful description of itself. This health check may indicate a bug: please open a Ceph bug report if you think you have encountered a bug. If you believe the error is transient, you may restart your manager daemon(s), or use `ceph mgr fail` on the active daemon to prompt a failover to another daemon. OSDs ---- OSD_DOWN ________ One or more OSDs are marked down. The ceph-osd daemon may have been stopped, or peer OSDs may be unable to reach the OSD over the network. Common causes include a stopped or crashed daemon, a down host, or a network outage. Verify the host is healthy, the daemon is started, and network is functioning. If the daemon has crashed, the daemon log file (``/var/log/ceph/ceph-osd.*``) may contain debugging information. OSD_<crush type>_DOWN _____________________ (e.g. OSD_HOST_DOWN, OSD_ROOT_DOWN) All the OSDs within a particular CRUSH subtree are marked down, for example all OSDs on a host. OSD_ORPHAN __________ An OSD is referenced in the CRUSH map hierarchy but does not exist. The OSD can be removed from the CRUSH hierarchy with: .. prompt:: bash $ ceph osd crush rm osd.<id> OSD_OUT_OF_ORDER_FULL _____________________ The utilization thresholds for `nearfull`, `backfillfull`, `full`, and/or `failsafe_full` are not ascending. In particular, we expect `nearfull < backfillfull`, `backfillfull < full`, and `full < failsafe_full`. The thresholds can be adjusted with: .. prompt:: bash $ ceph osd set-nearfull-ratio <ratio> ceph osd set-backfillfull-ratio <ratio> ceph osd set-full-ratio <ratio> OSD_FULL ________ One or more OSDs has exceeded the `full` threshold and is preventing the cluster from servicing writes. Utilization by pool can be checked with: .. prompt:: bash $ ceph df The currently defined `full` ratio can be seen with: .. prompt:: bash $ ceph osd dump | grep full_ratio A short-term workaround to restore write availability is to raise the full threshold by a small amount: .. prompt:: bash $ ceph osd set-full-ratio <ratio> New storage should be added to the cluster by deploying more OSDs or existing data should be deleted in order to free up space. OSD_BACKFILLFULL ________________ One or more OSDs has exceeded the `backfillfull` threshold or *would* exceed when the currently mapped backfills finish, which will prevent data from being allowed to rebalance to this device. This is an early warning that rebalancing may not be able to complete and that the cluster is approaching full. Utilization by pool can be checked with: .. prompt:: bash $ ceph df OSD_NEARFULL ____________ One or more OSDs has exceeded the `nearfull` threshold. This is an early warning that the cluster is approaching full. Utilization by pool can be checked with: .. prompt:: bash $ ceph df OSDMAP_FLAGS ____________ One or more cluster flags of interest has been set. These flags include: * *full* - the cluster is flagged as full and cannot serve writes * *pauserd*, *pausewr* - paused reads or writes * *noup* - OSDs are not allowed to start * *nodown* - OSD failure reports are being ignored, such that the monitors will not mark OSDs `down` * *noin* - OSDs that were previously marked `out` will not be marked back `in` when they start * *noout* - down OSDs will not automatically be marked out after the configured interval * *nobackfill*, *norecover*, *norebalance* - recovery or data rebalancing is suspended * *noscrub*, *nodeep_scrub* - scrubbing is disabled * *notieragent* - cache tiering activity is suspended With the exception of *full*, these flags can be set or cleared with: .. prompt:: bash $ ceph osd set <flag> ceph osd unset <flag> OSD_FLAGS _________ One or more OSDs or CRUSH {nodes,device classes} has a flag of interest set. These flags include: * *noup*: these OSDs are not allowed to start * *nodown*: failure reports for these OSDs will be ignored * *noin*: if these OSDs were previously marked `out` automatically after a failure, they will not be marked in when they start * *noout*: if these OSDs are down they will not automatically be marked `out` after the configured interval These flags can be set and cleared in batch with: .. prompt:: bash $ ceph osd set-group <flags> <who> ceph osd unset-group <flags> <who> For example: .. prompt:: bash $ ceph osd set-group noup,noout osd.0 osd.1 ceph osd unset-group noup,noout osd.0 osd.1 ceph osd set-group noup,noout host-foo ceph osd unset-group noup,noout host-foo ceph osd set-group noup,noout class-hdd ceph osd unset-group noup,noout class-hdd OLD_CRUSH_TUNABLES __________________ The CRUSH map is using very old settings and should be updated. The oldest tunables that can be used (i.e., the oldest client version that can connect to the cluster) without triggering this health warning is determined by the ``mon_crush_min_required_version`` config option. See :ref:`crush-map-tunables` for more information. OLD_CRUSH_STRAW_CALC_VERSION ____________________________ The CRUSH map is using an older, non-optimal method for calculating intermediate weight values for ``straw`` buckets. The CRUSH map should be updated to use the newer method (``straw_calc_version=1``). See :ref:`crush-map-tunables` for more information. CACHE_POOL_NO_HIT_SET _____________________ One or more cache pools is not configured with a *hit set* to track utilization, which will prevent the tiering agent from identifying cold objects to flush and evict from the cache. Hit sets can be configured on the cache pool with: .. prompt:: bash $ ceph osd pool set <poolname> hit_set_type <type> ceph osd pool set <poolname> hit_set_period <period-in-seconds> ceph osd pool set <poolname> hit_set_count <number-of-hitsets> ceph osd pool set <poolname> hit_set_fpp <target-false-positive-rate> OSD_NO_SORTBITWISE __________________ No pre-Luminous v12.y.z OSDs are running but the ``sortbitwise`` flag has not been set. The ``sortbitwise`` flag must be set before OSDs running Luminous v12.y.z or newer can start. You can safely set the flag with: .. prompt:: bash $ ceph osd set sortbitwise OSD_FILESTORE __________________ The Filestore OSD back end has been deprecated; the BlueStore back end has been the default objectstore for quite some time. Warn if OSDs are running Filestore. The 'mclock_scheduler' is not supported for Filestore OSDs. Therefore, the default 'osd_op_queue' is set to 'wpq' for Filestore OSDs and is enforced even if the user attempts to change it. Filestore OSDs can be listed with: .. prompt:: bash $ ceph report | jq -c '."osd_metadata" | .[] | select(.osd_objectstore | contains("filestore")) | {id, osd_objectstore}' In order to upgrade to Reef or later releases, any Filestore OSDs must first be migrated to BlueStore. When upgrading a release prior to Reef to Reef or later: if it is not feasible to migrate Filestore OSDs to BlueStore immediately, you can silence this warning temporarily with: .. prompt:: bash $ ceph health mute OSD_FILESTORE Since this migration can take considerable time to complete, we recommend that you begin the process well in advance of an update to Reef or later releases. POOL_FULL _________ One or more pools has reached its quota and is no longer allowing writes. Pool quotas and utilization can be seen with: .. prompt:: bash $ ceph df detail You can either raise the pool quota with: .. prompt:: bash $ ceph osd pool set-quota <poolname> max_objects <num-objects> ceph osd pool set-quota <poolname> max_bytes <num-bytes> or delete some existing data to reduce utilization. BLUEFS_SPILLOVER ________________ One or more OSDs that use the BlueStore backend have been allocated `db` partitions (storage space for metadata, normally on a faster device) but that space has filled, such that metadata has "spilled over" onto the normal slow device. This isn't necessarily an error condition or even unexpected, but if the administrator's expectation was that all metadata would fit on the faster device, it indicates that not enough space was provided. This warning can be disabled on all OSDs with: .. prompt:: bash $ ceph config set osd bluestore_warn_on_bluefs_spillover false Alternatively, it can be disabled on a specific OSD with: .. prompt:: bash $ ceph config set osd.123 bluestore_warn_on_bluefs_spillover false To provide more metadata space, the OSD in question could be destroyed and reprovisioned. This will involve data migration and recovery. It may also be possible to expand the LVM logical volume backing the `db` storage. If the underlying LV has been expanded, the OSD daemon needs to be stopped and BlueFS informed of the device size change with: .. prompt:: bash $ ceph-bluestore-tool bluefs-bdev-expand --path /var/lib/ceph/osd/ceph-$ID BLUEFS_AVAILABLE_SPACE ______________________ To check how much space is free for BlueFS do: .. prompt:: bash $ ceph daemon osd.123 bluestore bluefs available This will output up to 3 values: `BDEV_DB free`, `BDEV_SLOW free` and `available_from_bluestore`. `BDEV_DB` and `BDEV_SLOW` report amount of space that has been acquired by BlueFS and is considered free. Value `available_from_bluestore` denotes ability of BlueStore to relinquish more space to BlueFS. It is normal that this value is different from amount of BlueStore free space, as BlueFS allocation unit is typically larger than BlueStore allocation unit. This means that only part of BlueStore free space will be acceptable for BlueFS. BLUEFS_LOW_SPACE _________________ If BlueFS is running low on available free space and there is little `available_from_bluestore` one can consider reducing BlueFS allocation unit size. To simulate available space when allocation unit is different do: .. prompt:: bash $ ceph daemon osd.123 bluestore bluefs available <alloc-unit-size> BLUESTORE_FRAGMENTATION _______________________ As BlueStore works free space on underlying storage will get fragmented. This is normal and unavoidable but excessive fragmentation will cause slowdown. To inspect BlueStore fragmentation one can do: .. prompt:: bash $ ceph daemon osd.123 bluestore allocator score block Score is given in [0-1] range. [0.0 .. 0.4] tiny fragmentation [0.4 .. 0.7] small, acceptable fragmentation [0.7 .. 0.9] considerable, but safe fragmentation [0.9 .. 1.0] severe fragmentation, may impact BlueFS ability to get space from BlueStore If detailed report of free fragments is required do: .. prompt:: bash $ ceph daemon osd.123 bluestore allocator dump block In case when handling OSD process that is not running fragmentation can be inspected with `ceph-bluestore-tool`. Get fragmentation score: .. prompt:: bash $ ceph-bluestore-tool --path /var/lib/ceph/osd/ceph-123 --allocator block free-score And dump detailed free chunks: .. prompt:: bash $ ceph-bluestore-tool --path /var/lib/ceph/osd/ceph-123 --allocator block free-dump BLUESTORE_LEGACY_STATFS _______________________ In the Nautilus release, BlueStore tracks its internal usage statistics on a per-pool granular basis, and one or more OSDs have BlueStore volumes that were created prior to Nautilus. If *all* OSDs are older than Nautilus, this just means that the per-pool metrics are not available. However, if there is a mix of pre-Nautilus and post-Nautilus OSDs, the cluster usage statistics reported by ``ceph df`` will not be accurate. The old OSDs can be updated to use the new usage tracking scheme by stopping each OSD, running a repair operation, and the restarting it. For example, if ``osd.123`` needed to be updated,: .. prompt:: bash $ systemctl stop ceph-osd@123 ceph-bluestore-tool repair --path /var/lib/ceph/osd/ceph-123 systemctl start ceph-osd@123 This warning can be disabled with: .. prompt:: bash $ ceph config set global bluestore_warn_on_legacy_statfs false BLUESTORE_NO_PER_POOL_OMAP __________________________ Starting with the Octopus release, BlueStore tracks omap space utilization by pool, and one or more OSDs have volumes that were created prior to Octopus. If all OSDs are not running BlueStore with the new tracking enabled, the cluster will report and approximate value for per-pool omap usage based on the most recent deep-scrub. The old OSDs can be updated to track by pool by stopping each OSD, running a repair operation, and the restarting it. For example, if ``osd.123`` needed to be updated,: .. prompt:: bash $ systemctl stop ceph-osd@123 ceph-bluestore-tool repair --path /var/lib/ceph/osd/ceph-123 systemctl start ceph-osd@123 This warning can be disabled with: .. prompt:: bash $ ceph config set global bluestore_warn_on_no_per_pool_omap false BLUESTORE_NO_PER_PG_OMAP __________________________ Starting with the Pacific release, BlueStore tracks omap space utilization by PG, and one or more OSDs have volumes that were created prior to Pacific. Per-PG omap enables faster PG removal when PGs migrate. The older OSDs can be updated to track by PG by stopping each OSD, running a repair operation, and the restarting it. For example, if ``osd.123`` needed to be updated,: .. prompt:: bash $ systemctl stop ceph-osd@123 ceph-bluestore-tool repair --path /var/lib/ceph/osd/ceph-123 systemctl start ceph-osd@123 This warning can be disabled with: .. prompt:: bash $ ceph config set global bluestore_warn_on_no_per_pg_omap false BLUESTORE_DISK_SIZE_MISMATCH ____________________________ One or more OSDs using BlueStore has an internal inconsistency between the size of the physical device and the metadata tracking its size. This can lead to the OSD crashing in the future. The OSDs in question should be destroyed and reprovisioned. Care should be taken to do this one OSD at a time, and in a way that doesn't put any data at risk. For example, if osd ``$N`` has the error: .. prompt:: bash $ ceph osd out osd.$N while ! ceph osd safe-to-destroy osd.$N ; do sleep 1m ; done ceph osd destroy osd.$N ceph-volume lvm zap /path/to/device ceph-volume lvm create --osd-id $N --data /path/to/device BLUESTORE_NO_COMPRESSION ________________________ One or more OSDs is unable to load a BlueStore compression plugin. This can be caused by a broken installation, in which the ``ceph-osd`` binary does not match the compression plugins, or a recent upgrade that did not include a restart of the ``ceph-osd`` daemon. Verify that the package(s) on the host running the OSD(s) in question are correctly installed and that the OSD daemon(s) have been restarted. If the problem persists, check the OSD log for any clues as to the source of the problem. BLUESTORE_SPURIOUS_READ_ERRORS ______________________________ One or more OSDs using BlueStore detects spurious read errors at main device. BlueStore has recovered from these errors by retrying disk reads. Though this might show some issues with underlying hardware, I/O subsystem, etc. Which theoretically might cause permanent data corruption. Some observations on the root cause can be found at https://tracker.ceph.com/issues/22464 This alert doesn't require immediate response but corresponding host might need additional attention, e.g. upgrading to the latest OS/kernel versions and H/W resource utilization monitoring. This warning can be disabled on all OSDs with: .. prompt:: bash $ ceph config set osd bluestore_warn_on_spurious_read_errors false Alternatively, it can be disabled on a specific OSD with: .. prompt:: bash $ ceph config set osd.123 bluestore_warn_on_spurious_read_errors false Device health ------------- DEVICE_HEALTH _____________ One or more devices is expected to fail soon, where the warning threshold is controlled by the ``mgr/devicehealth/warn_threshold`` config option. This warning only applies to OSDs that are currently marked "in", so the expected response to this failure is to mark the device "out" so that data is migrated off of the device, and then to remove the hardware from the system. Note that the marking out is normally done automatically if ``mgr/devicehealth/self_heal`` is enabled based on the ``mgr/devicehealth/mark_out_threshold``. Device health can be checked with: .. prompt:: bash $ ceph device info <device-id> Device life expectancy is set by a prediction model run by the mgr or an by external tool via the command: .. prompt:: bash $ ceph device set-life-expectancy <device-id> <from> <to> You can change the stored life expectancy manually, but that usually doesn't accomplish anything as whatever tool originally set it will probably set it again, and changing the stored value does not affect the actual health of the hardware device. DEVICE_HEALTH_IN_USE ____________________ One or more devices is expected to fail soon and has been marked "out" of the cluster based on ``mgr/devicehealth/mark_out_threshold``, but it is still participating in one more PGs. This may be because it was only recently marked "out" and data is still migrating, or because data cannot be migrated off for some reason (e.g., the cluster is nearly full, or the CRUSH hierarchy is such that there isn't another suitable OSD to migrate the data too). This message can be silenced by disabling the self heal behavior (setting ``mgr/devicehealth/self_heal`` to false), by adjusting the ``mgr/devicehealth/mark_out_threshold``, or by addressing what is preventing data from being migrated off of the ailing device. DEVICE_HEALTH_TOOMANY _____________________ Too many devices is expected to fail soon and the ``mgr/devicehealth/self_heal`` behavior is enabled, such that marking out all of the ailing devices would exceed the clusters ``mon_osd_min_in_ratio`` ratio that prevents too many OSDs from being automatically marked "out". This generally indicates that too many devices in your cluster are expected to fail soon and you should take action to add newer (healthier) devices before too many devices fail and data is lost. The health message can also be silenced by adjusting parameters like ``mon_osd_min_in_ratio`` or ``mgr/devicehealth/mark_out_threshold``, but be warned that this will increase the likelihood of unrecoverable data loss in the cluster. Data health (pools & placement groups) -------------------------------------- PG_AVAILABILITY _______________ Data availability is reduced, meaning that the cluster is unable to service potential read or write requests for some data in the cluster. Specifically, one or more PGs is in a state that does not allow IO requests to be serviced. Problematic PG states include *peering*, *stale*, *incomplete*, and the lack of *active* (if those conditions do not clear quickly). Detailed information about which PGs are affected is available from: .. prompt:: bash $ ceph health detail In most cases the root cause is that one or more OSDs is currently down; see the discussion for ``OSD_DOWN`` above. The state of specific problematic PGs can be queried with: .. prompt:: bash $ ceph tell <pgid> query PG_DEGRADED ___________ Data redundancy is reduced for some data, meaning the cluster does not have the desired number of replicas for all data (for replicated pools) or erasure code fragments (for erasure coded pools). Specifically, one or more PGs: * has the *degraded* or *undersized* flag set, meaning there are not enough instances of that placement group in the cluster; * has not had the *clean* flag set for some time. Detailed information about which PGs are affected is available from: .. prompt:: bash $ ceph health detail In most cases the root cause is that one or more OSDs is currently down; see the discussion for ``OSD_DOWN`` above. The state of specific problematic PGs can be queried with: .. prompt:: bash $ ceph tell <pgid> query PG_RECOVERY_FULL ________________ Data redundancy may be reduced or at risk for some data due to a lack of free space in the cluster. Specifically, one or more PGs has the *recovery_toofull* flag set, meaning that the cluster is unable to migrate or recover data because one or more OSDs is above the *full* threshold. See the discussion for *OSD_FULL* above for steps to resolve this condition. PG_BACKFILL_FULL ________________ Data redundancy may be reduced or at risk for some data due to a lack of free space in the cluster. Specifically, one or more PGs has the *backfill_toofull* flag set, meaning that the cluster is unable to migrate or recover data because one or more OSDs is above the *backfillfull* threshold. See the discussion for *OSD_BACKFILLFULL* above for steps to resolve this condition. PG_DAMAGED __________ Data scrubbing has discovered some problems with data consistency in the cluster. Specifically, one or more PGs has the *inconsistent* or *snaptrim_error* flag is set, indicating an earlier scrub operation found a problem, or that the *repair* flag is set, meaning a repair for such an inconsistency is currently in progress. See :doc:`pg-repair` for more information. OSD_SCRUB_ERRORS ________________ Recent OSD scrubs have uncovered inconsistencies. This error is generally paired with *PG_DAMAGED* (see above). See :doc:`pg-repair` for more information. OSD_TOO_MANY_REPAIRS ____________________ When a read error occurs and another replica is available it is used to repair the error immediately, so that the client can get the object data. Scrub handles errors for data at rest. In order to identify possible failing disks that aren't seeing scrub errors, a count of read repairs is maintained. If it exceeds a config value threshold *mon_osd_warn_num_repaired* default 10, this health warning is generated. LARGE_OMAP_OBJECTS __________________ One or more pools contain large omap objects as determined by ``osd_deep_scrub_large_omap_object_key_threshold`` (threshold for number of keys to determine a large omap object) or ``osd_deep_scrub_large_omap_object_value_sum_threshold`` (the threshold for summed size (bytes) of all key values to determine a large omap object) or both. More information on the object name, key count, and size in bytes can be found by searching the cluster log for 'Large omap object found'. Large omap objects can be caused by RGW bucket index objects that do not have automatic resharding enabled. Please see :ref:`RGW Dynamic Bucket Index Resharding <rgw_dynamic_bucket_index_resharding>` for more information on resharding. The thresholds can be adjusted with: .. prompt:: bash $ ceph config set osd osd_deep_scrub_large_omap_object_key_threshold <keys> ceph config set osd osd_deep_scrub_large_omap_object_value_sum_threshold <bytes> CACHE_POOL_NEAR_FULL ____________________ A cache tier pool is nearly full. Full in this context is determined by the ``target_max_bytes`` and ``target_max_objects`` properties on the cache pool. Once the pool reaches the target threshold, write requests to the pool may block while data is flushed and evicted from the cache, a state that normally leads to very high latencies and poor performance. The cache pool target size can be adjusted with: .. prompt:: bash $ ceph osd pool set <cache-pool-name> target_max_bytes <bytes> ceph osd pool set <cache-pool-name> target_max_objects <objects> Normal cache flush and evict activity may also be throttled due to reduced availability or performance of the base tier, or overall cluster load. TOO_FEW_PGS ___________ The number of PGs in use in the cluster is below the configurable threshold of ``mon_pg_warn_min_per_osd`` PGs per OSD. This can lead to suboptimal distribution and balance of data across the OSDs in the cluster, and similarly reduce overall performance. This may be an expected condition if data pools have not yet been created. The PG count for existing pools can be increased or new pools can be created. Please refer to :ref:`choosing-number-of-placement-groups` for more information. POOL_PG_NUM_NOT_POWER_OF_TWO ____________________________ One or more pools has a ``pg_num`` value that is not a power of two. Although this is not strictly incorrect, it does lead to a less balanced distribution of data because some PGs have roughly twice as much data as others. This is easily corrected by setting the ``pg_num`` value for the affected pool(s) to a nearby power of two: .. prompt:: bash $ ceph osd pool set <pool-name> pg_num <value> This health warning can be disabled with: .. prompt:: bash $ ceph config set global mon_warn_on_pool_pg_num_not_power_of_two false POOL_TOO_FEW_PGS ________________ One or more pools should probably have more PGs, based on the amount of data that is currently stored in the pool. This can lead to suboptimal distribution and balance of data across the OSDs in the cluster, and similarly reduce overall performance. This warning is generated if the ``pg_autoscale_mode`` property on the pool is set to ``warn``. To disable the warning, you can disable auto-scaling of PGs for the pool entirely with: .. prompt:: bash $ ceph osd pool set <pool-name> pg_autoscale_mode off To allow the cluster to automatically adjust the number of PGs,: .. prompt:: bash $ ceph osd pool set <pool-name> pg_autoscale_mode on You can also manually set the number of PGs for the pool to the recommended amount with: .. prompt:: bash $ ceph osd pool set <pool-name> pg_num <new-pg-num> Please refer to :ref:`choosing-number-of-placement-groups` and :ref:`pg-autoscaler` for more information. TOO_MANY_PGS ____________ The number of PGs in use in the cluster is above the configurable threshold of ``mon_max_pg_per_osd`` PGs per OSD. If this threshold is exceed the cluster will not allow new pools to be created, pool `pg_num` to be increased, or pool replication to be increased (any of which would lead to more PGs in the cluster). A large number of PGs can lead to higher memory utilization for OSD daemons, slower peering after cluster state changes (like OSD restarts, additions, or removals), and higher load on the Manager and Monitor daemons. The simplest way to mitigate the problem is to increase the number of OSDs in the cluster by adding more hardware. Note that the OSD count used for the purposes of this health check is the number of "in" OSDs, so marking "out" OSDs "in" (if there are any) can also help: .. prompt:: bash $ ceph osd in <osd id(s)> Please refer to :ref:`choosing-number-of-placement-groups` for more information. POOL_TOO_MANY_PGS _________________ One or more pools should probably have more PGs, based on the amount of data that is currently stored in the pool. This can lead to higher memory utilization for OSD daemons, slower peering after cluster state changes (like OSD restarts, additions, or removals), and higher load on the Manager and Monitor daemons. This warning is generated if the ``pg_autoscale_mode`` property on the pool is set to ``warn``. To disable the warning, you can disable auto-scaling of PGs for the pool entirely with: .. prompt:: bash $ ceph osd pool set <pool-name> pg_autoscale_mode off To allow the cluster to automatically adjust the number of PGs,: .. prompt:: bash $ ceph osd pool set <pool-name> pg_autoscale_mode on You can also manually set the number of PGs for the pool to the recommended amount with: .. prompt:: bash $ ceph osd pool set <pool-name> pg_num <new-pg-num> Please refer to :ref:`choosing-number-of-placement-groups` and :ref:`pg-autoscaler` for more information. POOL_TARGET_SIZE_BYTES_OVERCOMMITTED ____________________________________ One or more pools have a ``target_size_bytes`` property set to estimate the expected size of the pool, but the value(s) exceed the total available storage (either by themselves or in combination with other pools' actual usage). This is usually an indication that the ``target_size_bytes`` value for the pool is too large and should be reduced or set to zero with: .. prompt:: bash $ ceph osd pool set <pool-name> target_size_bytes 0 For more information, see :ref:`specifying_pool_target_size`. POOL_HAS_TARGET_SIZE_BYTES_AND_RATIO ____________________________________ One or more pools have both ``target_size_bytes`` and ``target_size_ratio`` set to estimate the expected size of the pool. Only one of these properties should be non-zero. If both are set, ``target_size_ratio`` takes precedence and ``target_size_bytes`` is ignored. To reset ``target_size_bytes`` to zero: .. prompt:: bash $ ceph osd pool set <pool-name> target_size_bytes 0 For more information, see :ref:`specifying_pool_target_size`. TOO_FEW_OSDS ____________ The number of OSDs in the cluster is below the configurable threshold of ``osd_pool_default_size``. SMALLER_PGP_NUM _______________ One or more pools has a ``pgp_num`` value less than ``pg_num``. This is normally an indication that the PG count was increased without also increasing the placement behavior. This is sometimes done deliberately to separate out the `split` step when the PG count is adjusted from the data migration that is needed when ``pgp_num`` is changed. This is normally resolved by setting ``pgp_num`` to match ``pg_num``, triggering the data migration, with: .. prompt:: bash $ ceph osd pool set <pool> pgp_num <pg-num-value> MANY_OBJECTS_PER_PG ___________________ One or more pools has an average number of objects per PG that is significantly higher than the overall cluster average. The specific threshold is controlled by the ``mon_pg_warn_max_object_skew`` configuration value. This is usually an indication that the pool(s) containing most of the data in the cluster have too few PGs, and/or that other pools that do not contain as much data have too many PGs. See the discussion of *TOO_MANY_PGS* above. The threshold can be raised to silence the health warning by adjusting the ``mon_pg_warn_max_object_skew`` config option on the managers. The health warning will be silenced for a particular pool if ``pg_autoscale_mode`` is set to ``on``. POOL_APP_NOT_ENABLED ____________________ A pool exists that contains one or more objects but has not been tagged for use by a particular application. Resolve this warning by labeling the pool for use by an application. For example, if the pool is used by RBD,: .. prompt:: bash $ rbd pool init <poolname> If the pool is being used by a custom application 'foo', you can also label via the low-level command: .. prompt:: bash $ ceph osd pool application enable foo For more information, see :ref:`associate-pool-to-application`. POOL_FULL _________ One or more pools has reached (or is very close to reaching) its quota. The threshold to trigger this error condition is controlled by the ``mon_pool_quota_crit_threshold`` configuration option. Pool quotas can be adjusted up or down (or removed) with: .. prompt:: bash $ ceph osd pool set-quota <pool> max_bytes <bytes> ceph osd pool set-quota <pool> max_objects <objects> Setting the quota value to 0 will disable the quota. POOL_NEAR_FULL ______________ One or more pools is approaching a configured fullness threshold. One threshold that can trigger this warning condition is the ``mon_pool_quota_warn_threshold`` configuration option. Pool quotas can be adjusted up or down (or removed) with: .. prompt:: bash $ ceph osd pool set-quota <pool> max_bytes <bytes> ceph osd pool set-quota <pool> max_objects <objects> Setting the quota value to 0 will disable the quota. Other thresholds that can trigger the above two warning conditions are ``mon_osd_nearfull_ratio`` and ``mon_osd_full_ratio``. Visit the :ref:`storage-capacity` and :ref:`no-free-drive-space` documents for details and resolution. OBJECT_MISPLACED ________________ One or more objects in the cluster is not stored on the node the cluster would like it to be stored on. This is an indication that data migration due to some recent cluster change has not yet completed. Misplaced data is not a dangerous condition in and of itself; data consistency is never at risk, and old copies of objects are never removed until the desired number of new copies (in the desired locations) are present. OBJECT_UNFOUND ______________ One or more objects in the cluster cannot be found. Specifically, the OSDs know that a new or updated copy of an object should exist, but a copy of that version of the object has not been found on OSDs that are currently online. Read or write requests to unfound objects will block. Ideally, a down OSD can be brought back online that has the more recent copy of the unfound object. Candidate OSDs can be identified from the peering state for the PG(s) responsible for the unfound object: .. prompt:: bash $ ceph tell <pgid> query If the latest copy of the object is not available, the cluster can be told to roll back to a previous version of the object. See :ref:`failures-osd-unfound` for more information. SLOW_OPS ________ One or more OSD or monitor requests is taking a long time to process. This can be an indication of extreme load, a slow storage device, or a software bug. The request queue for the daemon in question can be queried with the following command, executed from the daemon's host: .. prompt:: bash $ ceph daemon osd.<id> ops A summary of the slowest recent requests can be seen with: .. prompt:: bash $ ceph daemon osd.<id> dump_historic_ops The location of an OSD can be found with: .. prompt:: bash $ ceph osd find osd.<id> PG_NOT_SCRUBBED _______________ One or more PGs has not been scrubbed recently. PGs are normally scrubbed within every configured interval specified by :confval:`osd_scrub_max_interval` globally. This interval can be overridden on per-pool basis with :confval:`scrub_max_interval`. The warning triggers when ``mon_warn_pg_not_scrubbed_ratio`` percentage of interval has elapsed without a scrub since it was due. PGs will not scrub if they are not flagged as *clean*, which may happen if they are misplaced or degraded (see *PG_AVAILABILITY* and *PG_DEGRADED* above). You can manually initiate a scrub of a clean PG with:: ceph pg scrub <pgid> PG_NOT_DEEP_SCRUBBED ____________________ One or more PGs has not been deep scrubbed recently. PGs are normally scrubbed every :confval:`osd_deep_scrub_interval` seconds, and this warning triggers when ``mon_warn_pg_not_deep_scrubbed_ratio`` percentage of interval has elapsed without a scrub since it was due. PGs will not (deep) scrub if they are not flagged as *clean*, which may happen if they are misplaced or degraded (see *PG_AVAILABILITY* and *PG_DEGRADED* above). You can manually initiate a scrub of a clean PG with: .. prompt:: bash $ ceph pg deep-scrub <pgid> PG_SLOW_SNAP_TRIMMING _____________________ The snapshot trim queue for one or more PGs has exceeded the configured warning threshold. This indicates that either an extremely large number of snapshots were recently deleted, or that the OSDs are unable to trim snapshots quickly enough to keep up with the rate of new snapshot deletions. The warning threshold is controlled by the ``mon_osd_snap_trim_queue_warn_on`` option (default: 32768). This warning may trigger if OSDs are under excessive load and unable to keep up with their background work, or if the OSDs' internal metadata database is heavily fragmented and unable to perform. It may also indicate some other performance issue with the OSDs. The exact size of the snapshot trim queue is reported by the ``snaptrimq_len`` field of ``ceph pg ls -f json-detail``. Miscellaneous ------------- RECENT_CRASH ____________ One or more Ceph daemons has crashed recently, and the crash has not yet been archived (acknowledged) by the administrator. This may indicate a software bug, a hardware problem (e.g., a failing disk), or some other problem. New crashes can be listed with: .. prompt:: bash $ ceph crash ls-new Information about a specific crash can be examined with: .. prompt:: bash $ ceph crash info <crash-id> This warning can be silenced by "archiving" the crash (perhaps after being examined by an administrator) so that it does not generate this warning: .. prompt:: bash $ ceph crash archive <crash-id> Similarly, all new crashes can be archived with: .. prompt:: bash $ ceph crash archive-all Archived crashes will still be visible via ``ceph crash ls`` but not ``ceph crash ls-new``. The time period for what "recent" means is controlled by the option ``mgr/crash/warn_recent_interval`` (default: two weeks). These warnings can be disabled entirely with: .. prompt:: bash $ ceph config set mgr/crash/warn_recent_interval 0 RECENT_MGR_MODULE_CRASH _______________________ One or more ceph-mgr modules has crashed recently, and the crash as not yet been archived (acknowledged) by the administrator. This generally indicates a software bug in one of the software modules run inside the ceph-mgr daemon. Although the module that experienced the problem maybe be disabled as a result, the function of other modules is normally unaffected. As with the *RECENT_CRASH* health alert, the crash can be inspected with: .. prompt:: bash $ ceph crash info <crash-id> This warning can be silenced by "archiving" the crash (perhaps after being examined by an administrator) so that it does not generate this warning: .. prompt:: bash $ ceph crash archive <crash-id> Similarly, all new crashes can be archived with: .. prompt:: bash $ ceph crash archive-all Archived crashes will still be visible via ``ceph crash ls`` but not ``ceph crash ls-new``. The time period for what "recent" means is controlled by the option ``mgr/crash/warn_recent_interval`` (default: two weeks). These warnings can be disabled entirely with: .. prompt:: bash $ ceph config set mgr/crash/warn_recent_interval 0 TELEMETRY_CHANGED _________________ Telemetry has been enabled, but the contents of the telemetry report have changed since that time, so telemetry reports will not be sent. The Ceph developers periodically revise the telemetry feature to include new and useful information, or to remove information found to be useless or sensitive. If any new information is included in the report, Ceph will require the administrator to re-enable telemetry to ensure they have an opportunity to (re)review what information will be shared. To review the contents of the telemetry report: .. prompt:: bash $ ceph telemetry show Note that the telemetry report consists of several optional channels that may be independently enabled or disabled. For more information, see :ref:`telemetry`. To re-enable telemetry (and make this warning go away): .. prompt:: bash $ ceph telemetry on To disable telemetry (and make this warning go away): .. prompt:: bash $ ceph telemetry off AUTH_BAD_CAPS _____________ One or more auth users has capabilities that cannot be parsed by the monitor. This generally indicates that the user will not be authorized to perform any action with one or more daemon types. This error is mostly likely to occur after an upgrade if the capabilities were set with an older version of Ceph that did not properly validate their syntax, or if the syntax of the capabilities has changed. The user in question can be removed with: .. prompt:: bash $ ceph auth rm <entity-name> (This will resolve the health alert, but obviously clients will not be able to authenticate as that user.) Alternatively, the capabilities for the user can be updated with: .. prompt:: bash $ ceph auth <entity-name> <daemon-type> <caps> [<daemon-type> <caps> ...] For more information about auth capabilities, see :ref:`user-management`. OSD_NO_DOWN_OUT_INTERVAL ________________________ The ``mon_osd_down_out_interval`` option is set to zero, which means that the system will not automatically perform any repair or healing operations after an OSD fails. Instead, an administrator (or some other external entity) will need to manually mark down OSDs as 'out' (i.e., via ``ceph osd out <osd-id>``) in order to trigger recovery. This option is normally set to five or ten minutes--enough time for a host to power-cycle or reboot. This warning can silenced by setting the ``mon_warn_on_osd_down_out_interval_zero`` to false: .. prompt:: bash $ ceph config global mon mon_warn_on_osd_down_out_interval_zero false DASHBOARD_DEBUG _______________ The Dashboard debug mode is enabled. This means, if there is an error while processing a REST API request, the HTTP error response contains a Python traceback. This behaviour should be disabled in production environments because such a traceback might contain and expose sensible information. The debug mode can be disabled with: .. prompt:: bash $ ceph dashboard debug disable 6: Testing 5: Load Balancing 4: Ceph Configuration 3: Enabling RADOS 2: PreRequisites 1: Reasoning Maintenance and Monitoring Reading and References Back to the top…