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Monitor Config Reference

Understanding how to configure a Ceph Monitor is an important part of building a reliable Ceph Storage Cluster. All Ceph Storage Clusters have at least one monitor. The monitor complement usually remains fairly consistent, but you can add, remove or replace a monitor in a cluster. See Adding/Removing a Monitor for details.

Background

Ceph Monitors maintain a “master copy” of the Cluster Map.

The Cluster Map makes it possible for Ceph clients to determine the location of all Ceph Monitors, Ceph OSD Daemons, and Ceph Metadata Servers. Clients do this by connecting to one Ceph Monitor and retrieving a current cluster map. Ceph clients must connect to a Ceph Monitor before they can read from or write to Ceph OSD Daemons or Ceph Metadata Servers. A Ceph client that has a current copy of the cluster map and the CRUSH algorithm can compute the location of any RADOS object within the cluster. This makes it possible for Ceph clients to talk directly to Ceph OSD Daemons. Direct communication between clients and Ceph OSD Daemons improves upon traditional storage architectures that required clients to communicate with a central component. See Scalability and High Availability for more on this subject.

The Ceph Monitor’s primary function is to maintain a master copy of the cluster map. Monitors also provide authentication and logging services. All changes in the monitor services are written by the Ceph Monitor to a single Paxos instance, and Paxos writes the changes to a key/value store. This provides strong consistency. Ceph Monitors are able to query the most recent version of the cluster map during sync operations, and they use the key/value store’s snapshots and iterators (using RocksDB) to perform store-wide synchronization.

Cluster Maps

The cluster map is a composite of maps, including the monitor map, the OSD map, the placement group map and the metadata server map. The cluster map tracks a number of important things: which processes are in the Ceph Storage Cluster; which processes that are in the Ceph Storage Cluster are up and running or down; whether, the placement groups are active or inactive, and clean or in some other state; and, other details that reflect the current state of the cluster such as the total amount of storage space, and the amount of storage used.

When there is a significant change in the state of the cluster–e.g., a Ceph OSD Daemon goes down, a placement group falls into a degraded state, etc.–the cluster map gets updated to reflect the current state of the cluster. Additionally, the Ceph Monitor also maintains a history of the prior states of the cluster. The monitor map, OSD map, placement group map and metadata server map each maintain a history of their map versions. We call each version an “epoch.”

When operating your Ceph Storage Cluster, keeping track of these states is an important part of your system administration duties. See Monitoring a Cluster and Monitoring OSDs and PGs for additional details.

Monitor Quorum

Our Configuring ceph section provides a trivial Ceph configuration file that provides for one monitor in the test cluster. A cluster will run fine with a single monitor; however, a single monitor is a single-point-of-failure. To ensure high availability in a production Ceph Storage Cluster, you should run Ceph with multiple monitors so that the failure of a single monitor WILL NOT bring down your entire cluster.

When a Ceph Storage Cluster runs multiple Ceph Monitors for high availability, Ceph Monitors use Paxos to establish consensus about the master cluster map. A consensus requires a majority of monitors running to establish a quorum for consensus about the cluster map (e.g., 1; 2 out of 3; 3 out of 5; 4 out of 6; etc.).

mon_force_quorum_join

Force monitor to join quorum even if it has been previously removed from the map

type

bool

default

false

Consistency

When you add monitor settings to your Ceph configuration file, you need to be aware of some of the architectural aspects of Ceph Monitors. Ceph imposes strict consistency requirements for a Ceph monitor when discovering another Ceph Monitor within the cluster. Whereas, Ceph Clients and other Ceph daemons use the Ceph configuration file to discover monitors, monitors discover each other using the monitor map (monmap), not the Ceph configuration file.

A Ceph Monitor always refers to the local copy of the monmap when discovering other Ceph Monitors in the Ceph Storage Cluster. Using the monmap instead of the Ceph configuration file avoids errors that could break the cluster (e.g., typos in ceph.conf when specifying a monitor address or port). Since monitors use monmaps for discovery and they share monmaps with clients and other Ceph daemons, the monmap provides monitors with a strict guarantee that their consensus is valid.

Strict consistency also applies to updates to the monmap. As with any other updates on the Ceph Monitor, changes to the monmap always run through a distributed consensus algorithm called Paxos. The Ceph Monitors must agree on each update to the monmap, such as adding or removing a Ceph Monitor, to ensure that each monitor in the quorum has the same version of the monmap. Updates to the monmap are incremental so that Ceph Monitors have the latest agreed upon version, and a set of previous versions. Maintaining a history enables a Ceph Monitor that has an older version of the monmap to catch up with the current state of the Ceph Storage Cluster.

If Ceph Monitors were to discover each other through the Ceph configuration file instead of through the monmap, additional risks would be introduced because Ceph configuration files are not updated and distributed automatically. Ceph Monitors might inadvertently use an older Ceph configuration file, fail to recognize a Ceph Monitor, fall out of a quorum, or develop a situation where Paxos is not able to determine the current state of the system accurately.

Bootstrapping Monitors

In most configuration and deployment cases, tools that deploy Ceph help bootstrap the Ceph Monitors by generating a monitor map for you (e.g., cephadm, etc). A Ceph Monitor requires a few explicit settings:

Filesystem ID: The fsid is the unique identifier for your object store. Since you can run multiple clusters on the same hardware, you must specify the unique ID of the object store when bootstrapping a monitor. Deployment tools usually do this for you (e.g., cephadm can call a tool like uuidgen), but you may specify the fsid manually too.
Monitor ID: A monitor ID is a unique ID assigned to each monitor within the cluster. It is an alphanumeric value, and by convention the identifier usually follows an alphabetical increment (e.g., a, b, etc.). This can be set in a Ceph configuration file (e.g., [mon.a], [mon.b], etc.), by a deployment tool, or using the ceph commandline.
Keys: The monitor must have secret keys. A deployment tool such as cephadm usually does this for you, but you may perform this step manually too. See Monitor Keyrings for details.

For additional details on bootstrapping, see Bootstrapping a Monitor.

Configuring Monitors

To apply configuration settings to the entire cluster, enter the configuration settings under [global]. To apply configuration settings to all monitors in your cluster, enter the configuration settings under [mon]. To apply configuration settings to specific monitors, specify the monitor instance (e.g., [mon.a]). By convention, monitor instance names use alpha notation.

[global]

[mon]

[mon.a]

[mon.b]

[mon.c]

Minimum Configuration

The bare minimum monitor settings for a Ceph monitor via the Ceph configuration file include a hostname and a network address for each monitor. You can configure these under [mon] or under the entry for a specific monitor.

[global]
        mon host = 10.0.0.2,10.0.0.3,10.0.0.4

[mon.a]
        host = hostname1
        mon addr = 10.0.0.10:6789

See the Network Configuration Reference for details.

Note

This minimum configuration for monitors assumes that a deployment tool generates the fsid and the mon. key for you.

Once you deploy a Ceph cluster, you SHOULD NOT change the IP addresses of monitors. However, if you decide to change the monitor’s IP address, you must follow a specific procedure. See Changing a Monitor’s IP Address for details.

Monitors can also be found by clients by using DNS SRV records. See Monitor lookup through DNS for details.

Cluster ID

Each Ceph Storage Cluster has a unique identifier (fsid). If specified, it usually appears under the [global] section of the configuration file. Deployment tools usually generate the fsid and store it in the monitor map, so the value may not appear in a configuration file. The fsid makes it possible to run daemons for multiple clusters on the same hardware.

fsid

The cluster ID. One per cluster. May be generated by a deployment tool if not specified.

type

uuid

Note

Do not set this value if you use a deployment tool that does it for you.

Initial Members

We recommend running a production Ceph Storage Cluster with at least three Ceph Monitors to ensure high availability. When you run multiple monitors, you may specify the initial monitors that must be members of the cluster in order to establish a quorum. This may reduce the time it takes for your cluster to come online.

[mon]
        mon_initial_members = a,b,c

mon_initial_members

The IDs of initial monitors in a cluster during startup. If specified, Ceph requires an odd number of monitors to form an initial quorum (e.g., 3).

type

str

Note

A majority of monitors in your cluster must be able to reach each other in order to establish a quorum. You can decrease the initial number of monitors to establish a quorum with this setting.

Data

Ceph provides a default path where Ceph Monitors store data. For optimal performance in a production Ceph Storage Cluster, we recommend running Ceph Monitors on separate hosts and drives from Ceph OSD Daemons. As leveldb uses mmap() for writing the data, Ceph Monitors flush their data from memory to disk very often, which can interfere with Ceph OSD Daemon workloads if the data store is co-located with the OSD Daemons.

In Ceph versions 0.58 and earlier, Ceph Monitors store their data in plain files. This approach allows users to inspect monitor data with common tools like ls and cat. However, this approach didn’t provide strong consistency.

In Ceph versions 0.59 and later, Ceph Monitors store their data as key/value pairs. Ceph Monitors require ACID transactions. Using a data store prevents recovering Ceph Monitors from running corrupted versions through Paxos, and it enables multiple modification operations in one single atomic batch, among other advantages.

Generally, we do not recommend changing the default data location. If you modify the default location, we recommend that you make it uniform across Ceph Monitors by setting it in the [mon] section of the configuration file.

mon_data

The monitor’s data location.

type

str

default

/var/lib/ceph/mon/$cluster-$id

mon_data_size_warn

Raise HEALTH_WARN status when a monitor’s data store grows to be larger than this size, 15GB by default.

type

size

default

15Gi

mon_data_avail_warn

Raise HEALTH_WARN status when the filesystem that houses a monitor’s data store reports that its available capacity is less than or equal to this percentage .

type

int

default

30

mon_data_avail_crit

Raise HEALTH_ERR status when the filesystem that houses a monitor’s data store reports that its available capacity is less than or equal to this percentage.

type

int

default

5

mon_warn_on_cache_pools_without_hit_sets

Raise HEALTH_WARN when a cache pool does not have the hit_set_type value configured. See hit_set_type for more details.

type

bool

default

true

mon_warn_on_crush_straw_calc_version_zero

Raise HEALTH_WARN when the CRUSH straw_calc_version is zero. See CRUSH map tunables for details.

type

bool

default

true

mon_warn_on_legacy_crush_tunables

Raise HEALTH_WARN when CRUSH tunables are too old (older than mon_min_crush_required_version)

type

bool

default

true

see also

mon_crush_min_required_version

mon_crush_min_required_version

The minimum tunable profile required by the cluster. See CRUSH map tunables for details.

type

str

default

hammer

see also

mon_warn_on_legacy_crush_tunables

mon_warn_on_osd_down_out_interval_zero

Raise HEALTH_WARN when mon_osd_down_out_interval is zero. Having this option set to zero on the leader acts much like the noout flag. It’s hard to figure out what’s going wrong with clusters without the noout flag set but acting like that just the same, so we report a warning in this case.

type

bool

default

true

see also

mon_osd_down_out_interval

mon_warn_on_slow_ping_ratio

Raise HEALTH_WARN when any heartbeat between OSDs exceeds mon_warn_on_slow_ping_ratio of osd_heartbeat_grace.

type

float

default

0.05

see also

osd_heartbeat_grace, mon_warn_on_slow_ping_time

mon_warn_on_slow_ping_time

Override mon_warn_on_slow_ping_ratio with a specific value. Raise HEALTH_WARN if any heartbeat between OSDs exceeds mon_warn_on_slow_ping_time milliseconds. The default is 0 (disabled).

type

float

default

0.0

see also

mon_warn_on_slow_ping_ratio

mon_warn_on_pool_no_redundancy

Raise HEALTH_WARN if any pool is configured with no replicas.

type

bool

default

true

see also

osd_pool_default_size, osd_pool_default_min_size

mon_cache_target_full_warn_ratio

Position between pool’s cache_target_full and target_max_object where we start warning

type

float

default

0.66

mon_health_to_clog

Enable sending a health summary to the cluster log periodically.

type

bool

default

true

mon_health_to_clog_tick_interval

How often (in seconds) the monitor sends a health summary to the cluster log (a non-positive number disables). If current health summary is empty or identical to the last time, monitor will not send it to cluster log.

type

float

default

1 minute

mon_health_to_clog_interval

How often (in seconds) the monitor sends a health summary to the cluster log (a non-positive number disables). Monitors will always send a summary to the cluster log whether or not it differs from the previous summary.

type

int

default

10 minutes

see also

mon_health_to_clog

Storage Capacity

When a Ceph Storage Cluster gets close to its maximum capacity (see``mon_osd_full ratio``), Ceph prevents you from writing to or reading from OSDs as a safety measure to prevent data loss. Therefore, letting a production Ceph Storage Cluster approach its full ratio is not a good practice, because it sacrifices high availability. The default full ratio is .95, or 95% of capacity. This a very aggressive setting for a test cluster with a small number of OSDs.

Tip

When monitoring your cluster, be alert to warnings related to the nearfull ratio. This means that a failure of some OSDs could result in a temporary service disruption if one or more OSDs fails. Consider adding more OSDs to increase storage capacity.

A common scenario for test clusters involves a system administrator removing an OSD from the Ceph Storage Cluster, watching the cluster rebalance, then removing another OSD, and another, until at least one OSD eventually reaches the full ratio and the cluster locks up. We recommend a bit of capacity planning even with a test cluster. Planning enables you to gauge how much spare capacity you will need in order to maintain high availability. Ideally, you want to plan for a series of Ceph OSD Daemon failures where the cluster can recover to an active+clean state without replacing those OSDs immediately. Cluster operation continues in the active+degraded state, but this is not ideal for normal operation and should be addressed promptly.

The following diagram depicts a simplistic Ceph Storage Cluster containing 33 Ceph Nodes with one OSD per host, each OSD reading from and writing to a 3TB drive. So this exemplary Ceph Storage Cluster has a maximum actual capacity of 99TB. With a mon osd full ratio of 0.95, if the Ceph Storage Cluster falls to 5TB of remaining capacity, the cluster will not allow Ceph Clients to read and write data. So the Ceph Storage Cluster’s operating capacity is 95TB, not 99TB.

It is normal in such a cluster for one or two OSDs to fail. A less frequent but reasonable scenario involves a rack’s router or power supply failing, which brings down multiple OSDs simultaneously (e.g., OSDs 7-12). In such a scenario, you should still strive for a cluster that can remain operational and achieve an active + clean state–even if that means adding a few hosts with additional OSDs in short order. If your capacity utilization is too high, you may not lose data, but you could still sacrifice data availability while resolving an outage within a failure domain if capacity utilization of the cluster exceeds the full ratio. For this reason, we recommend at least some rough capacity planning.

Identify two numbers for your cluster:

The number of OSDs.
The total capacity of the cluster

If you divide the total capacity of your cluster by the number of OSDs in your cluster, you will find the mean average capacity of an OSD within your cluster. Consider multiplying that number by the number of OSDs you expect will fail simultaneously during normal operations (a relatively small number). Finally multiply the capacity of the cluster by the full ratio to arrive at a maximum operating capacity; then, subtract the number of amount of data from the OSDs you expect to fail to arrive at a reasonable full ratio. Repeat the foregoing process with a higher number of OSD failures (e.g., a rack of OSDs) to arrive at a reasonable number for a near full ratio.

The following settings only apply on cluster creation and are then stored in the OSDMap. To clarify, in normal operation the values that are used by OSDs are those found in the OSDMap, not those in the configuration file or central config store.

[global]
        mon_osd_full_ratio = .80
        mon_osd_backfillfull_ratio = .75
        mon_osd_nearfull_ratio = .70

mon_osd_full_ratio

Description: The threshold percentage of device space utilized before an OSD is considered full.
Type: Float
Default: 0.95

mon_osd_backfillfull_ratio

Description: The threshold percentage of device space utilized before an OSD is considered too full to backfill.
Type: Float
Default: 0.90

mon_osd_nearfull_ratio

Description: The threshold percentage of device space used before an OSD is considered nearfull.
Type: Float
Default: 0.85

Tip

If some OSDs are nearfull, but others have plenty of capacity, you may have an inaccurate CRUSH weight set for the nearfull OSDs.

Tip

These settings only apply during cluster creation. Afterwards they need to be changed in the OSDMap using ceph osd set-nearfull-ratio and ceph osd set-full-ratio

Heartbeat

Ceph monitors know about the cluster by requiring reports from each OSD, and by receiving reports from OSDs about the status of their neighboring OSDs. Ceph provides reasonable default settings for monitor/OSD interaction; however, you may modify them as needed. See Monitor/OSD Interaction for details.

Monitor Store Synchronization

When you run a production cluster with multiple monitors (recommended), each monitor checks to see if a neighboring monitor has a more recent version of the cluster map (e.g., a map in a neighboring monitor with one or more epoch numbers higher than the most current epoch in the map of the instant monitor). Periodically, one monitor in the cluster may fall behind the other monitors to the point where it must leave the quorum, synchronize to retrieve the most current information about the cluster, and then rejoin the quorum. For the purposes of synchronization, monitors may assume one of three roles:

Leader: The Leader is the first monitor to achieve the most recent Paxos version of the cluster map.
Provider: The Provider is a monitor that has the most recent version of the cluster map, but wasn’t the first to achieve the most recent version.
Requester: A Requester is a monitor that has fallen behind the leader and must synchronize in order to retrieve the most recent information about the cluster before it can rejoin the quorum.

These roles enable a leader to delegate synchronization duties to a provider, which prevents synchronization requests from overloading the leader–improving performance. In the following diagram, the requester has learned that it has fallen behind the other monitors. The requester asks the leader to synchronize, and the leader tells the requester to synchronize with a provider.

Synchronization always occurs when a new monitor joins the cluster. During runtime operations, monitors may receive updates to the cluster map at different times. This means the leader and provider roles may migrate from one monitor to another. If this happens while synchronizing (e.g., a provider falls behind the leader), the provider can terminate synchronization with a requester.

Once synchronization is complete, Ceph performs trimming across the cluster. Trimming requires that the placement groups are active+clean.

mon_sync_timeout

Number of seconds the monitor will wait for the next update message from its sync provider before it gives up and bootstrap again.

type

float

default

1 minute

mon_sync_max_payload_size

The maximum size for a sync payload (in bytes).

type

size

default

1Mi

paxos_max_join_drift

The maximum Paxos iterations before we must first sync the monitor data stores. When a monitor finds that its peer is too far ahead of it, it will first sync with data stores before moving on.

type

int

default

10

paxos_stash_full_interval

How often (in commits) to stash a full copy of the PaxosService state. Current this setting only affects mds, mon, auth and mgr PaxosServices.

type

int

default

25

paxos_propose_interval

Gather updates for this time interval before proposing a map update.

type

float

default

1.0

paxos_min

The minimum number of Paxos states to keep around

type

int

default

500

paxos_min_wait

The minimum amount of time to gather updates after a period of inactivity.

type

float

default

0.05

paxos_trim_min

Number of extra proposals tolerated before trimming

type

int

default

250

paxos_trim_max

The maximum number of extra proposals to trim at a time

type

int

default

500

paxos_service_trim_min

The minimum amount of versions to trigger a trim (0 disables it)

type

uint

default

250

paxos_service_trim_max

The maximum amount of versions to trim during a single proposal (0 disables it)

type

uint

default

500

paxos_service_trim_max_multiplier

factor by which paxos_service_trim_max will be multiplied to get a new upper bound when trim sizes are high (0 disables it)

type

uint

default

20

min

0

mon_mds_force_trim_to

Force monitor to trim mdsmaps up to but not including this FSMap epoch. A value of 0 disables (the default) this config. This command is potentially dangerous, use with care.

type

int

default

0

mon_osd_force_trim_to

Force monitor to trim osdmaps to this point, even if there is PGs not clean at the specified epoch (0 disables it. dangerous, use with care)

type

int

default

0

mon_osd_cache_size

The size of osdmaps cache, not to rely on underlying store’s cache

type

int

default

500

mon_election_timeout

On election proposer, maximum waiting time for all ACKs in seconds.

type

float

default

5.0

mon_lease

The length (in seconds) of the lease on the monitor’s versions.

type

float

default

5.0

mon_lease_renew_interval_factor

mon_lease * mon_lease_renew_interval_factor will be the interval for the Leader to renew the other monitor’s leases. The factor should be less than 1.0.

type

float

default

0.6

allowed range

[0, 0.9999999]

see also

mon_lease

mon_lease_ack_timeout_factor

The Leader will wait mon_lease * mon_lease_ack_timeout_factor for the Providers to acknowledge the lease extension.

type

float

default

2.0

allowed range

[1.0001, 100]

see also

mon_lease

mon_accept_timeout_factor

The Leader will wait mon_lease * mon_accept_timeout_factor for the Requester(s) to accept a Paxos update. It is also used during the Paxos recovery phase for similar purposes.

type

float

default

2.0

see also

mon_lease

mon_min_osdmap_epochs

Minimum number of OSD map epochs to keep at all times.

type

int

default

500

mon_max_log_epochs

Maximum number of Log epochs the monitor should keep.

type

int

default

500

Clock

Ceph daemons pass critical messages to each other, which must be processed before daemons reach a timeout threshold. If the clocks in Ceph monitors are not synchronized, it can lead to a number of anomalies. For example:

Daemons ignoring received messages (e.g., timestamps outdated)
Timeouts triggered too soon/late when a message wasn’t received in time.

See Monitor Store Synchronization for details.

Tip

You must configure NTP or PTP daemons on your Ceph monitor hosts to ensure that the monitor cluster operates with synchronized clocks. It can be advantageous to have monitor hosts sync with each other as well as with multiple quality upstream time sources.

Clock drift may still be noticeable with NTP even though the discrepancy is not yet harmful. Ceph’s clock drift / clock skew warnings may get triggered even though NTP maintains a reasonable level of synchronization. Increasing your clock drift may be tolerable under such circumstances; however, a number of factors such as workload, network latency, configuring overrides to default timeouts and the Monitor Store Synchronization settings may influence the level of acceptable clock drift without compromising Paxos guarantees.

Ceph provides the following tunable options to allow you to find acceptable values.

mon_tick_interval

A monitor’s tick interval in seconds.

type

int

default

5

mon_clock_drift_allowed

allowed clock drift (in seconds) between mons before issuing a health warning

type

float

default

0.05

mon_clock_drift_warn_backoff

exponential backoff factor for logging clock drift warnings in the cluster log

type

float

default

5.0

mon_timecheck_interval

The time check interval (clock drift check) in seconds for the Leader.

type

float

default

5 minutes

mon_timecheck_skew_interval

The time check interval (clock drift check) in seconds when in presence of a skew in seconds for the Leader.

type

float

default

30.0

see also

mon_timecheck_interval

Client

mon_client_hunt_interval

The client will try a new monitor every N seconds until it establishes a connection.

type

float

default

3.0

mon_client_ping_interval

The client will ping the monitor every N seconds.

type

float

default

10.0

mon_client_max_log_entries_per_message

The maximum number of log entries a monitor will generate per client message.

type

int

default

1000

mon_client_bytes

The amount of client message data allowed in memory (in bytes).

type

size

default

100Mi

Pool settings

Since version v0.94 there is support for pool flags which allow or disallow changes to be made to pools. Monitors can also disallow removal of pools if appropriately configured. The inconvenience of this guardrail is far outweighed by the number of accidental pool (and thus data) deletions it prevents.

mon_allow_pool_delete

Should monitors allow pools to be removed, regardless of what the pool flags say?

type

bool

default

false

osd_pool_default_ec_fast_read

Whether to turn on fast read on the pool or not. It will be used as the default setting of newly created erasure coded pools if fast_read is not specified at create time.

type

bool

default

false

osd_pool_default_flag_hashpspool

set hashpspool (better hashing scheme) flag on new pools

type

bool

default

true

osd_pool_default_flag_nodelete

Set the nodelete flag on new pools, which prevents pool removal.

type

bool

default

false

osd_pool_default_flag_nopgchange

Set the nopgchange flag on new pools. Does not allow the number of PGs to be changed.

type

bool

default

false

osd_pool_default_flag_nosizechange

Set the nosizechange flag on new pools. Does not allow the size to be changed.

type

bool

default

false

For more information about the pool flags see Pool values.

Miscellaneous

mon_max_osd

The maximum number of OSDs allowed in the cluster.

type

int

default

10000

mon_globalid_prealloc

The number of global IDs to pre-allocate for clients and daemons in the cluster.

type

uint

default

10000

mon_subscribe_interval

The refresh interval (in seconds) for subscriptions. The subscription mechanism enables obtaining cluster maps and log information.

type

float

default

1 day

mon_stat_smooth_intervals

Ceph will smooth statistics over the last N PG maps.

type

uint

default

6

min

1

mon_probe_timeout

Number of seconds the monitor will wait to find peers before bootstrapping.

type

float

default

2.0

mon_daemon_bytes

The message memory cap for metadata server and OSD messages (in bytes).

type

size

default

400Mi

mon_max_log_entries_per_event

The maximum number of log entries per event.

type

int

default

4096

mon_osd_prime_pg_temp

Enables or disables priming the PGMap with the previous OSDs when an out OSD comes back into the cluster. With the true setting, clients will continue to use the previous OSDs until the newly in OSDs for a PG have peered.

type

bool

default

true

mon_osd_prime_pg_temp_max_time

How much time in seconds the monitor should spend trying to prime the PGMap when an out OSD comes back into the cluster.

type

float

default

0.5

mon_osd_prime_pg_temp_max_estimate

Maximum estimate of time spent on each PG before we prime all PGs in parallel.

type

float

default

0.25

mon_mds_skip_sanity

Skip safety assertions on FSMap (in case of bugs where we want to continue anyway). Monitor terminates if the FSMap sanity check fails, but we can disable it by enabling this option.

type

bool

default

false

mon_max_mdsmap_epochs

The maximum number of mdsmap epochs to trim during a single proposal.

type

int

default

500

mon_config_key_max_entry_size

The maximum size of config-key entry (in bytes)

type

size

default

64Ki

mon_scrub_interval

How often the monitor scrubs its store by comparing the stored checksums with the computed ones for all stored keys. (0 disables it. dangerous, use with care)

type

secs

default

1 day

mon_scrub_max_keys

The maximum number of keys to scrub each time.

type

int

default

100

mon_compact_on_start

Compact the database used as Ceph Monitor store on ceph-mon start. A manual compaction helps to shrink the monitor database and improve the performance of it if the regular compaction fails to work.

type

bool

default

false

mon_compact_on_bootstrap

Compact the database used as Ceph Monitor store on bootstrap. Monitors probe each other to establish a quorum after bootstrap. If a monitor times out before joining the quorum, it will start over and bootstrap again.

type

bool

default

false

mon_compact_on_trim

Compact a certain prefix (including paxos) when we trim its old states.

type

bool

default

true

mon_cpu_threads

Number of threads for performing CPU intensive work on monitor.

type

int

default

4

mon_osd_mapping_pgs_per_chunk

We calculate the mapping from placement group to OSDs in chunks. This option specifies the number of placement groups per chunk.

type

int

default

4096

mon_session_timeout

Monitor will terminate inactive sessions stay idle over this time limit.

type

int

default

5 minutes

mon_osd_cache_size_min

The minimum amount of bytes to be kept mapped in memory for osd monitor caches.

type

size

default

128Mi

mon_memory_target

The amount of bytes pertaining to OSD monitor caches and KV cache to be kept mapped in memory with cache auto-tuning enabled.

type

size

default

2Gi

mon_memory_autotune

Autotune the cache memory used for OSD monitors and KV database.

type

bool

default

true