Appendix C. Ceph Monitor configuration options

The following are Ceph monitor configuration options that can be set up during deployment.

mon_initial_members
Description
The IDs of initial monitors in a cluster during startup. If specified, Ceph requires an odd number of monitors to form an initial quorum (for example, 3).
Type
String
Default
None
mon_force_quorum_join
Description
Force monitor to join quorum even if it has been previously removed from the map
Type
Boolean
Default
False
mon_dns_srv_name
Description
The service name used for querying the DNS for the monitor hosts/addresses.
Type
String
Default
ceph-mon
fsid
Description
The cluster ID. One per cluster.
Type
UUID
Required
Yes.
Default
N/A. May be generated by a deployment tool if not specified.
mon_data
Description
The monitor’s data location.
Type
String
Default
/var/lib/ceph/mon/$cluster-$id
mon_data_size_warn
Description
Ceph issues a HEALTH_WARN status in the cluster log when the monitor’s data store reaches this threshold. The default value is 15GB.
Type
Integer
Default
15*1024*1024*1024*`
mon_data_avail_warn
Description
Ceph issues a HEALTH_WARN status in cluster log when the available disk space of the monitor’s data store is lower than or equal to this percentage.
Type
Integer
Default
30
mon_data_avail_crit
Description
Ceph issues a HEALTH_ERR status in cluster log when the available disk space of the monitor’s data store is lower or equal to this percentage.
Type
Integer
Default
5
mon_warn_on_cache_pools_without_hit_sets
Description
Ceph issues a HEALTH_WARN status in cluster log if a cache pool does not have the hit_set_type paramater set.
Type
Boolean
Default
True
mon_warn_on_crush_straw_calc_version_zero
Description
Ceph issues a HEALTH_WARN status in the cluster log if the CRUSH’s straw_calc_version is zero. See CRUSH tunables for details.
Type
Boolean
Default
True
mon_warn_on_legacy_crush_tunables
Description
Ceph issues a HEALTH_WARN status in the cluster log if CRUSH tunables are too old (older than mon_min_crush_required_version).
Type
Boolean
Default
True
mon_crush_min_required_version
Description
This setting defines the minimum tunable profile version required by the cluster.
Type
String
Default
firefly
mon_warn_on_osd_down_out_interval_zero
Description
Ceph issues a HEALTH_WARN status in the cluster log if the mon_osd_down_out_interval setting is zero, because the Leader behaves in a similar manner when the noout flag is set. Administrators find it easier to troubleshoot a cluster by setting the noout flag. Ceph issues the warning to ensure administrators know that the setting is zero.
Type
Boolean
Default
True
mon_cache_target_full_warn_ratio
Description
Ceph issues a warning when between the ratio of cache_target_full and target_max_object.
Type
Float
Default
0.66
mon_health_data_update_interval
Description
How often (in seconds) a monitor in the quorum shares its health status with its peers. A negative number disables health updates.
Type
Float
Default
60
mon_health_to_clog
Description
This setting enable Ceph to send a health summary to the cluster log periodically.
Type
Boolean
Default
True
mon_health_to_clog_tick_interval
Description
How often (in seconds) the monitor sends a health summary to the cluster log. A non-positive number disables it. If the current health summary is empty or identical to the last time, the monitor will not send the status to the cluster log.
Type
Integer
Default
3600
mon_health_to_clog_interval
Description
How often (in seconds) the monitor sends a health summary to the cluster log. A non-positive number disables it. The monitor will always send the summary to cluster log.
Type
Integer
Default
60
mon_osd_full_ratio
Description
The percentage of disk space used before an OSD is considered full.
Type
Float:
Default
.95
mon_osd_nearfull_ratio
Description
The percentage of disk space used before an OSD is considered nearfull.
Type
Float
Default
.85
mon_sync_trim_timeout
Description, Type
Double
Default
30.0
mon_sync_heartbeat_timeout
Description, Type
Double
Default
30.0
mon_sync_heartbeat_interval
Description, Type
Double
Default
5.0
mon_sync_backoff_timeout
Description, Type
Double
Default
30.0
mon_sync_timeout
Description
Number of seconds the monitor will wait for the next update message from its sync provider before it gives up and bootstraps again.
Type
Double
Default
30.0
mon_sync_max_retries
Description, Type
Integer
Default
5
mon_sync_max_payload_size
Description
The maximum size for a sync payload (in bytes).
Type
32-bit Integer
Default
1045676
paxos_max_join_drift
Description
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
Integer
Default
10
paxos_stash_full_interval
Description
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
Integer
Default
25
paxos_propose_interval
Description
Gather updates for this time interval before proposing a map update.
Type
Double
Default
1.0
paxos_min
Description
The minimum number of paxos states to keep around
Type
Integer
Default
500
paxos_min_wait
Description
The minimum amount of time to gather updates after a period of inactivity.
Type
Double
Default
0.05
paxos_trim_min
Description
Number of extra proposals tolerated before trimming
Type
Integer
Default
250
paxos_trim_max
Description
The maximum number of extra proposals to trim at a time
Type
Integer
Default
500
paxos_service_trim_min
Description
The minimum amount of versions to trigger a trim (0 disables it)
Type
Integer
Default
250
paxos_service_trim_max
Description
The maximum amount of versions to trim during a single proposal (0 disables it)
Type
Integer
Default
500
mon_max_log_epochs
Description
The maximum amount of log epochs to trim during a single proposal
Type
Integer
Default
500
mon_max_pgmap_epochs
Description
The maximum amount of pgmap epochs to trim during a single proposal
Type
Integer
Default
500
mon_mds_force_trim_to
Description
Force monitor to trim mdsmaps to this point (0 disables it. dangerous, use with care)
Type
Integer
Default
0
mon_osd_force_trim_to
Description
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
Integer
Default
0
mon_osd_cache_size
Description
The size of osdmaps cache, not to rely on underlying store’s cache
Type
Integer
Default
10
mon_election_timeout
Description
On election proposer, maximum waiting time for all ACKs in seconds.
Type
Float
Default
5
mon_lease
Description
The length (in seconds) of the lease on the monitor’s versions.
Type
Float
Default
5
mon_lease_renew_interval_factor
Description
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
mon_lease_ack_timeout_factor
Description
The Leader will wait mon lease * mon lease ack timeout factor for the Providers to acknowledge the lease extension.
Type
Float
Default
2.0
mon_accept_timeout_factor
Description
The Leader will wait mon lease * mon accept timeout factor for the Requesters to accept a Paxos update. It is also used during the Paxos recovery phase for similar purposes.
Type
Float
Default
2.0
mon_min_osdmap_epochs
Description
Minimum number of OSD map epochs to keep at all times.
Type
32-bit Integer
Default
500
mon_max_pgmap_epochs
Description
Maximum number of PG map epochs the monitor should keep.
Type
32-bit Integer
Default
500
mon_max_log_epochs
Description
Maximum number of Log epochs the monitor should keep.
Type
32-bit Integer
Default
500
clock_offset
Description
How much to offset the system clock. See Clock.cc for details.
Type
Double
Default
0
mon_tick_interval
Description
A monitor’s tick interval in seconds.
Type
32-bit Integer
Default
5
mon_clock_drift_allowed
Description
The clock drift in seconds allowed between monitors.
Type
Float
Default
.050
mon_clock_drift_warn_backoff
Description
Exponential backoff for clock drift warnings.
Type
Float
Default
5
mon_timecheck_interval
Description
The time check interval (clock drift check) in seconds for the leader.
Type
Float
Default
300.0
mon_timecheck_skew_interval
Description
The time check interval (clock drift check) in seconds when in the presence of a skew in seconds for the Leader.
Type
Float
Default
30.0
mon_max_osd
Description
The maximum number of OSDs allowed in the cluster.
Type
32-bit Integer
Default
10000
mon_globalid_prealloc
Description
The number of global IDs to pre-allocate for clients and daemons in the cluster.
Type
32-bit Integer
Default
100
mon_sync_fs_threshold
Description
Synchronize with the filesystem when writing the specified number of objects. Set it to 0 to disable it.
Type
32-bit Integer
Default
5
mon_subscribe_interval
Description
The refresh interval, in seconds, for subscriptions. The subscription mechanism enables obtaining the cluster maps and log information.
Type
Double
Default
300
mon_stat_smooth_intervals
Description
Ceph will smooth statistics over the last N PG maps.
Type
Integer
Default
2
mon_probe_timeout
Description
Number of seconds the monitor will wait to find peers before bootstrapping.
Type
Double
Default
2.0
mon_daemon_bytes
Description
The message memory cap for metadata server and OSD messages (in bytes).
Type
64-bit Integer Unsigned
Default
400ul << 20
mon_max_log_entries_per_event
Description
The maximum number of log entries per event.
Type
Integer
Default
4096
mon_osd_prime_pg_temp
Description
Enables or disable priming the PGMap with the previous OSDs when an out OSD comes back into the cluster. With the true setting the clients will continue to use the previous OSDs until the newly in OSDs as that PG peered.
Type
Boolean
Default
true
mon_osd_prime_pg_temp_max_time
Description
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_time_estimate
Description
Maximum estimate of time spent on each PG before we prime all PGs in parallel.
Type
Float
Default
0.25
mon_osd_allow_primary_affinity
Description
allow primary_affinity to be set in the osdmap.
Type
Boolean
Default
False
mon_osd_pool_ec_fast_read
Description
Whether turn on fast read on the pool or not. It will be used as the default setting of newly created erasure pools if fast_read is not specified at create time.
Type
Boolean
Default
False
mon_mds_skip_sanity
Description
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
Boolean
Default
False
mon_max_mdsmap_epochs
Description
The maximum amount of mdsmap epochs to trim during a single proposal.
Type
Integer
Default
500
mon_config_key_max_entry_size
Description
The maximum size of config-key entry (in bytes).
Type
Integer
Default
4096
mon_scrub_interval
Description
How often, in seconds, the monitor scrub its store by comparing the stored checksums with the computed ones of all the stored keys.
Type
Integer
Default
3600*24
mon_scrub_max_keys
Description
The maximum number of keys to scrub each time.
Type
Integer
Default
100
mon_compact_on_start
Description
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
Boolean
Default
False
mon_compact_on_bootstrap
Description
Compact the database used as Ceph Monitor store on on bootstrap. Monitor starts probing each other for creating a quorum after bootstrap. If it times out before joining the quorum, it will start over and bootstrap itself again.
Type
Boolean
Default
False
mon_compact_on_trim
Description
Compact a certain prefix (including paxos) when we trim its old states.
Type
Boolean
Default
True
mon_cpu_threads
Description
Number of threads for performing CPU intensive work on monitor.
Type
Boolean
Default
True
mon_osd_mapping_pgs_per_chunk
Description
We calculate the mapping from placement group to OSDs in chunks. This option specifies the number of placement groups per chunk.
Type
Integer
Default
4096
mon_osd_max_split_count
Description
Largest number of PGs per "involved" OSD to let split create. When we increase the pg_num of a pool, the placement groups will be splitted on all OSDs serving that pool. We want to avoid extreme multipliers on PG splits.
Type
Integer
Default
300
rados_mon_op_timeout
Description
Number of seconds to wait for a response from the monitor before returning an error from a rados operation. 0 means at limit, or no wait time.
Type
Double
Default
0

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