Appendix G. Object Storage Daemon (OSD) configuration options The following are Ceph Object Storage Daemon (OSD) configuration options that can be set during deployment. You can set these configuration options with the ceph config set osd CONFIGURATION_OPTION VALUE command. osd_uuid Description The universally unique identifier (UUID) for the Ceph OSD. Type UUID Default The UUID. Note The osd uuid applies to a single Ceph OSD. The fsid applies to the entire cluster. osd_data Description The path to the OSD's data. You must create the directory when deploying Ceph. Mount a drive for OSD data at this mount point. Type String Default /var/lib/ceph/osd/USDcluster-USDid osd_max_write_size Description The maximum size of a write in megabytes. Type 32-bit Integer Default 90 osd_client_message_size_cap Description The largest client data message allowed in memory. Type 64-bit Integer Unsigned Default 500MB default. 500*1024L*1024L osd_class_dir Description The class path for RADOS class plug-ins. Type String Default USDlibdir/rados-classes osd_max_scrubs Description The maximum number of simultaneous scrub operations for a Ceph OSD. Type 32-bit Int Default 1 osd_scrub_thread_timeout Description The maximum time in seconds before timing out a scrub thread. Type 32-bit Integer Default 60 osd_scrub_finalize_thread_timeout Description The maximum time in seconds before timing out a scrub finalize thread. Type 32-bit Integer Default 60*10 osd_scrub_begin_hour Description This restricts scrubbing to this hour of the day or later. Use osd_scrub_begin_hour = 0 and osd_scrub_end_hour = 0 to allow scrubbing the entire day. Along with osd_scrub_end_hour , they define a time window, in which the scrubs can happen. But a scrub is performed no matter whether the time window allows or not, as long as the placement group's scrub interval exceeds osd_scrub_max_interval . Type Integer Default 0 Allowed range [0,23] osd_scrub_end_hour Description This restricts scrubbing to the hour earlier than this. Use osd_scrub_begin_hour = 0 and osd_scrub_end_hour = 0 to allow scrubbing for the entire day. Along with osd_scrub_begin_hour , they define a time window, in which the scrubs can happen. But a scrub is performed no matter whether the time window allows or not, as long as the placement group's scrub interval exceeds osd_scrub_max_interval . Type Integer Default 0 Allowed range [0,23] osd_scrub_load_threshold Description The maximum load. Ceph will not scrub when the system load (as defined by the getloadavg() function) is higher than this number. Default is 0.5 . Type Float Default 0.5 osd_scrub_min_interval Description The minimum interval in seconds for scrubbing the Ceph OSD when the Red Hat Ceph Storage cluster load is low. Type Float Default Once per day. 60*60*24 osd_scrub_max_interval Description The maximum interval in seconds for scrubbing the Ceph OSD irrespective of cluster load. Type Float Default Once per week. 7*60*60*24 osd_scrub_interval_randomize_ratio Description Takes the ratio and randomizes the scheduled scrub between osd scrub min interval and osd scrub max interval . Type Float Default 0.5 . mon_warn_not_scrubbed Description Number of seconds after osd_scrub_interval to warn about any PGs that were not scrubbed. Type Integer Default 0 (no warning). osd_scrub_chunk_min Description The object store is partitioned into chunks which end on hash boundaries. For chunky scrubs, Ceph scrubs objects one chunk at a time with writes blocked for that chunk. The osd scrub chunk min setting represents the minimum number of chunks to scrub. Type 32-bit Integer Default 5 osd_scrub_chunk_max Description The maximum number of chunks to scrub. Type 32-bit Integer Default 25 osd_scrub_sleep Description The time to sleep between deep scrub operations. Type Float Default 0 (or off). osd_scrub_during_recovery Description Allows scrubbing during recovery. Type Bool Default false osd_scrub_invalid_stats Description Forces extra scrub to fix stats marked as invalid. Type Bool Default true osd_scrub_priority Description Controls queue priority of scrub operations versus client I/O. Type Unsigned 32-bit Integer Default 5 osd_requested_scrub_priority Description The priority set for user requested scrub on the work queue. If this value were to be smaller than osd_client_op_priority , it can be boosted to the value of osd_client_op_priority when scrub is blocking client operations. Type Unsigned 32-bit Integer Default 120 osd_scrub_cost Description Cost of scrub operations in megabytes for queue scheduling purposes. Type Unsigned 32-bit Integer Default 52428800 osd_deep_scrub_interval Description The interval for deep scrubbing, that is fully reading all data. The osd scrub load threshold parameter does not affect this setting. Type Float Default Once per week. 60*60*24*7 osd_deep_scrub_stride Description Read size when doing a deep scrub. Type 32-bit Integer Default 512 KB. 524288 mon_warn_not_deep_scrubbed Description Number of seconds after osd_deep_scrub_interval to warn about any PGs that were not scrubbed. Type Integer Default 0 (no warning) osd_deep_scrub_randomize_ratio Description The rate at which scrubs will randomly become deep scrubs (even before osd_deep_scrub_interval has passed). Type Float Default 0.15 or 15% osd_deep_scrub_update_digest_min_age Description How many seconds old objects must be before scrub updates the whole-object digest. Type Integer Default 7200 (120 hours) osd_deep_scrub_large_omap_object_key_threshold Description Warning when you encounter an object with more OMAP keys than this. Type Integer Default 200000 osd_deep_scrub_large_omap_object_value_sum_threshold Description Warning when you encounter an object with more OMAP key bytes than this. Type Integer Default 1 G osd_op_num_shards Description The number of shards for client operations. Type 32-bit Integer Default 0 osd_op_num_threads_per_shard Description The number of threads per shard for client operations. Type 32-bit Integer Default 0 osd_op_num_shards_hdd Description The number of shards for HDD operations. Type 32-bit Integer Default 5 osd_op_num_threads_per_shard_hdd Description The number of threads per shard for HDD operations. Type 32-bit Integer Default 1 osd_op_num_shards_ssd Description The number of shards for SSD operations. Type 32-bit Integer Default 8 osd_op_num_threads_per_shard_ssd Description The number of threads per shard for SSD operations. Type 32-bit Integer Default 2 osd_client_op_priority Description The priority set for client operations. It is relative to osd recovery op priority . Type 32-bit Integer Default 63 Valid Range 1-63 osd_recovery_op_priority Description The priority set for recovery operations. It is relative to osd client op priority . Type 32-bit Integer Default 3 Valid Range 1-63 osd_op_thread_timeout Description The Ceph OSD operation thread timeout in seconds. Type 32-bit Integer Default 15 osd_op_complaint_time Description An operation becomes complaint worthy after the specified number of seconds have elapsed. Type Float Default 30 osd_disk_threads Description The number of disk threads, which are used to perform background disk intensive OSD operations such as scrubbing and snap trimming. Type 32-bit Integer Default 1 osd_op_history_size Description The maximum number of completed operations to track. Type 32-bit Unsigned Integer Default 20 osd_op_history_duration Description The oldest completed operation to track. Type 32-bit Unsigned Integer Default 600 osd_op_log_threshold Description How many operations logs to display at once. Type 32-bit Integer Default 5 osd_op_timeout Description The time in seconds after which running OSD operations time out. Type Integer Default 0 Important Do not set the osd op timeout option unless your clients can handle the consequences. For example, setting this parameter on clients running in virtual machines can lead to data corruption because the virtual machines interpret this timeout as a hardware failure. osd_max_backfills Description The maximum number of backfill operations allowed to or from a single OSD. Type 64-bit Unsigned Integer Default 1 osd_backfill_scan_min Description The minimum number of objects per backfill scan. Type 32-bit Integer Default 64 osd_backfill_scan_max Description The maximum number of objects per backfill scan. Type 32-bit Integer Default 512 osd_backfill_full_ratio Description Refuse to accept backfill requests when the Ceph OSD's full ratio is above this value. Type Float Default 0.85 osd_backfill_retry_interval Description The number of seconds to wait before retrying backfill requests. Type Double Default 30.000000 osd_map_dedup Description Enable removing duplicates in the OSD map. Type Boolean Default true osd_map_cache_size Description The size of the OSD map cache in megabytes. Type 32-bit Integer Default 50 osd_map_cache_bl_size Description The size of the in-memory OSD map cache in OSD daemons. Type 32-bit Integer Default 50 osd_map_cache_bl_inc_size Description The size of the in-memory OSD map cache incrementals in OSD daemons. Type 32-bit Integer Default 100 osd_map_message_max Description The maximum map entries allowed per MOSDMap message. Type 32-bit Integer Default 40 osd_snap_trim_thread_timeout Description The maximum time in seconds before timing out a snap trim thread. Type 32-bit Integer Default 60*60*1 osd_pg_max_concurrent_snap_trims Description The max number of parallel snap trims/PG. This controls how many objects per PG to trim at once. Type 32-bit Integer Default 2 osd_snap_trim_sleep Description Insert a sleep between every trim operation a PG issues. Type 32-bit Integer Default 0 osd_max_trimming_pgs Description The max number of trimming PGs Type 32-bit Integer Default 2 osd_backlog_thread_timeout Description The maximum time in seconds before timing out a backlog thread. Type 32-bit Integer Default 60*60*1 osd_default_notify_timeout Description The OSD default notification timeout (in seconds). Type 32-bit Integer Unsigned Default 30 osd_check_for_log_corruption Description Check log files for corruption. Can be computationally expensive. Type Boolean Default false osd_remove_thread_timeout Description The maximum time in seconds before timing out a remove OSD thread. Type 32-bit Integer Default 60*60 osd_command_thread_timeout Description The maximum time in seconds before timing out a command thread. Type 32-bit Integer Default 10*60 osd_command_max_records Description Limits the number of lost objects to return. Type 32-bit Integer Default 256 osd_auto_upgrade_tmap Description Uses tmap for omap on old objects. Type Boolean Default true osd_tmapput_sets_users_tmap Description Uses tmap for debugging only. Type Boolean Default false osd_preserve_trimmed_log Description Preserves trimmed log files, but uses more disk space. Type Boolean Default false osd_recovery_delay_start Description After peering completes, Ceph delays for the specified number of seconds before starting to recover objects. Type Float Default 0 osd_recovery_max_active Description The number of active recovery requests per OSD at one time. More requests will accelerate recovery, but the requests place an increased load on the cluster. Type 32-bit Integer Default 0 osd_recovery_max_chunk Description The maximum size of a recovered chunk of data to push. Type 64-bit Integer Unsigned Default 8388608 osd_recovery_threads Description The number of threads for recovering data. Type 32-bit Integer Default 1 osd_recovery_thread_timeout Description The maximum time in seconds before timing out a recovery thread. Type 32-bit Integer Default 30 osd_recover_clone_overlap Description Preserves clone overlap during recovery. Should always be set to true . Type Boolean Default true rados_osd_op_timeout Description Number of seconds that RADOS waits for a response from the OSD before returning an error from a RADOS operation. A value of 0 means no limit. Type Double Default 0

Commands:
IMPORTANT: Red Hat does not recommend changing the default.