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 CephFS health messages), and health checks that are defined by ceph-mgr python modules.

Definitions

Monitor

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 subsequen 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 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:

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:

ceph config set global mon_data_size_warn <size>

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:

ceph osd crush rm osd.<id>

OSD_OUT_OF_ORDER_FULL

The utilization thresholds for backfillfull, nearfull, full, and/or failsafe_full are not ascending. In particular, we expect backfillfull < nearfull, nearfull < full, and full < failsafe_full.

The thresholds can be adjusted with:

ceph osd set-backfillfull-ratio <ratio>
ceph osd set-nearfull-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:

ceph df

The currently defined full ratio can be seen with:

ceph osd dump | grep full_ratio

A short-term workaround to restore write availability is to raise the full threshold by a small amount:

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, 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:

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:

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:

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:

ceph osd set-group <flags> <who>
ceph osd unset-group <flags> <who>

For example,

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 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 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:

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 luminous v12.y.z or newer OSDs can start. You can safely set the flag with:

ceph osd set sortbitwise

POOL_FULL

One or more pools has reached its quota and is no longer allowing writes.

Pool quotas and utilization can be seen with:

ceph df detail

You can either raise the pool quota with:

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:

ceph config set osd bluestore_warn_on_bluefs_spillover false

Alternatively, it can be disabled on a specific OSD with:

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:

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:

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:

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:

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:

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:

ceph-bluestore-tool --path /var/lib/ceph/osd/ceph-123 --allocator block free-score

And dump detailed free chunks:

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,:

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:

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,:

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:

ceph config set global bluestore_warn_on_no_per_pool_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,:

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.

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:

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:

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:

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:

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:

ceph health detail

In most cases the root cause is that one or more OSDs is currently down; see the dicussion for OSD_DOWN above.

The state of specific problematic PGs can be queried with:

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 Repairing PG inconsistencies for more information.

OSD_SCRUB_ERRORS

Recent OSD scrubs have uncovered inconsistencies. This error is generally paired with PG_DAMAGED (see above).

See Repairing PG inconsistencies for more information.

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 RGW Dynamic Bucket Index Resharding for more information on resharding.

The thresholds can be adjusted with:

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:

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 Choosing the number of Placement Groups for more information.

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:

ceph osd pool set <pool-name> pg_autoscale_mode off

To allow the cluster to automatically adjust the number of PGs,:

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:

ceph osd pool set <pool-name> pg_num <new-pg-num>

Please refer to Choosing the number of Placement Groups and Autoscaling placement groups 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:

ceph osd in <osd id(s)>

Please refer to Choosing the 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:

ceph osd pool set <pool-name> pg_autoscale_mode off

To allow the cluster to automatically adjust the number of PGs,:

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:

ceph osd pool set <pool-name> pg_num <new-pg-num>

Please refer to Choosing the number of Placement Groups and Autoscaling placement groups for more information.

POOL_TARGET_SIZE_RATIO_OVERCOMMITTED

One or more pools have a target_size_ratio property set to estimate the expected size of the pool as a fraction of total storage, 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_ratio value for the pool is too large and should be reduced or set to zero with:

ceph osd pool set <pool-name> target_size_ratio 0

For more information, see Specifying expected pool size.

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:

ceph osd pool set <pool-name> target_size_bytes 0

For more information, see Specifying expected pool 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:

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.

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,:

rbd pool init <poolname>

If the pool is being used by a custom application ‘foo’, you can also label via the low-level command:

ceph osd pool application enable foo

For more information, see 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:

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 is quota. The threshold to trigger this warning condition is controlled by the mon_pool_quota_warn_threshold configuration option.

Pool quotas can be adjusted up or down (or removed) with:

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.

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:

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 Unfound Objects for more information.

SLOW_OPS

One or more OSD 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 on the OSD(s) in question can be queried with the following command, executed from the OSD host:

ceph daemon osd.<id> ops

A summary of the slowest recent requests can be seen with:

ceph daemon osd.<id> dump_historic_ops

The location of an OSD can be found with:

ceph osd find osd.<id>

PG_NOT_SCRUBBED

One or more PGs has not been scrubbed recently. PGs are normally scrubbed every mon_scrub_interval seconds, and this 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 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:

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:

ceph crash ls-new

Information about a specific crash can be examined with:

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:

ceph crash archive <crash-id>

Similarly, all new crashes can be archived with:

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:

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,:

ceph telemetry show

Note that the telemetry report consists of several optional channels that may be independently enabled or disabled. For more information, see Telemetry Module.

To re-enable telemetry (and make this warning go away),:

ceph telemetry on

To disable telemetry (and make this warning go away),:

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:

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:

ceph auth <entity-name> <daemon-type> <caps> [<daemon-type> <caps> ...]

For more information about auth capabilities, see 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:

ceph config global mon mon_warn_on_osd_down_out_interval_zero false