关于Redis配置信息初始化

关于Redis配置信息

Redis Server服务启动过程中，一般需要指定一个配置文件，官方默认配置文件为redis.conf，该文件用于指示Redis运行时状态、处理数据策略等方面。

使用配置文件/path/to/redis.conf来启动Redis Server服务，执行命令如下所示：

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./redis-server /path/to/redis.conf

如果在服务启动时，未指定配置文件，则Redis会使用默认的配置项。

Redis Server有一个全局变量static_configs，其存储着157个(v7.0版本)服务默认使用的通用配置项(默认配置可被自定义配置覆盖)，如果包含一些其他特殊的配置，整个配置项可能会更多。

默认配置项信息，如下所示：

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// 代码位置：src/config.c
// 默认配置项数组(除了 #ifdef USE_OPENSSL 对应的配置项)公共的配置项157个
standardConfig static_configs[] = {
    /* Bool configs */
    /* name, alias, flags, config_addr, default, is_valid, apply */
    createBoolConfig("rdbchecksum", NULL, IMMUTABLE_CONFIG, server.rdb_checksum, 1, NULL, NULL),
    createBoolConfig("daemonize", NULL, IMMUTABLE_CONFIG, server.daemonize, 0, NULL, NULL),
    createBoolConfig("io-threads-do-reads", NULL, DEBUG_CONFIG | IMMUTABLE_CONFIG, server.io_threads_do_reads, 0,NULL, NULL), /* Read + parse from threads? */
    createBoolConfig("always-show-logo", NULL, IMMUTABLE_CONFIG, server.always_show_logo, 0, NULL, NULL),
    createBoolConfig("protected-mode", NULL, MODIFIABLE_CONFIG, server.protected_mode, 1, NULL, NULL),
    createBoolConfig("rdbcompression", NULL, MODIFIABLE_CONFIG, server.rdb_compression, 1, NULL, NULL),
    createBoolConfig("rdb-del-sync-files", NULL, MODIFIABLE_CONFIG, server.rdb_del_sync_files, 0, NULL, NULL),
    createBoolConfig("activerehashing", NULL, MODIFIABLE_CONFIG, server.activerehashing, 1, NULL, NULL),
    createBoolConfig("stop-writes-on-bgsave-error", NULL, MODIFIABLE_CONFIG, server.stop_writes_on_bgsave_err, 1, NULL, NULL),
    createBoolConfig("set-proc-title", NULL, IMMUTABLE_CONFIG, server.set_proc_title, 1, NULL, NULL), /* Should setproctitle be used? */
    createBoolConfig("dynamic-hz", NULL, MODIFIABLE_CONFIG, server.dynamic_hz, 1, NULL, NULL), /* Adapt hz to # of clients.*/
    createBoolConfig("lazyfree-lazy-eviction", NULL, DEBUG_CONFIG | MODIFIABLE_CONFIG, server.lazyfree_lazy_eviction, 0, NULL, NULL),
    createBoolConfig("lazyfree-lazy-expire", NULL, DEBUG_CONFIG | MODIFIABLE_CONFIG, server.lazyfree_lazy_expire, 0, NULL, NULL),
    createBoolConfig("lazyfree-lazy-server-del", NULL, DEBUG_CONFIG | MODIFIABLE_CONFIG, server.lazyfree_lazy_server_del, 0, NULL, NULL),
    createBoolConfig("lazyfree-lazy-user-del", NULL, DEBUG_CONFIG | MODIFIABLE_CONFIG, server.lazyfree_lazy_user_del , 0, NULL, NULL),
    createBoolConfig("lazyfree-lazy-user-flush", NULL, DEBUG_CONFIG | MODIFIABLE_CONFIG, server.lazyfree_lazy_user_flush , 0, NULL, NULL),
    createBoolConfig("repl-disable-tcp-nodelay", NULL, MODIFIABLE_CONFIG, server.repl_disable_tcp_nodelay, 0, NULL, NULL),
    createBoolConfig("repl-diskless-sync", NULL, DEBUG_CONFIG | MODIFIABLE_CONFIG, server.repl_diskless_sync, 1, NULL, NULL),
    createBoolConfig("aof-rewrite-incremental-fsync", NULL, MODIFIABLE_CONFIG, server.aof_rewrite_incremental_fsync, 1, NULL, NULL),
    createBoolConfig("no-appendfsync-on-rewrite", NULL, MODIFIABLE_CONFIG, server.aof_no_fsync_on_rewrite, 0, NULL, NULL),
    createBoolConfig("cluster-require-full-coverage", NULL, MODIFIABLE_CONFIG, server.cluster_require_full_coverage, 1, NULL, NULL),
    createBoolConfig("rdb-save-incremental-fsync", NULL, MODIFIABLE_CONFIG, server.rdb_save_incremental_fsync, 1, NULL, NULL),
    createBoolConfig("aof-load-truncated", NULL, MODIFIABLE_CONFIG, server.aof_load_truncated, 1, NULL, NULL),
    createBoolConfig("aof-use-rdb-preamble", NULL, MODIFIABLE_CONFIG, server.aof_use_rdb_preamble, 1, NULL, NULL),
    createBoolConfig("aof-timestamp-enabled", NULL, MODIFIABLE_CONFIG, server.aof_timestamp_enabled, 0, NULL, NULL),
    createBoolConfig("cluster-replica-no-failover", "cluster-slave-no-failover", MODIFIABLE_CONFIG, server.cluster_slave_no_failover, 0, NULL, updateClusterFlags), /* Failover by default. */
    createBoolConfig("replica-lazy-flush", "slave-lazy-flush", MODIFIABLE_CONFIG, server.repl_slave_lazy_flush, 0, NULL, NULL),
    createBoolConfig("replica-serve-stale-data", "slave-serve-stale-data", MODIFIABLE_CONFIG, server.repl_serve_stale_data, 1, NULL, NULL),
    createBoolConfig("replica-read-only", "slave-read-only", DEBUG_CONFIG | MODIFIABLE_CONFIG, server.repl_slave_ro, 1, NULL, NULL),
    createBoolConfig("replica-ignore-maxmemory", "slave-ignore-maxmemory", MODIFIABLE_CONFIG, server.repl_slave_ignore_maxmemory, 1, NULL, NULL),
    createBoolConfig("jemalloc-bg-thread", NULL, MODIFIABLE_CONFIG, server.jemalloc_bg_thread, 1, NULL, updateJemallocBgThread),
    createBoolConfig("activedefrag", NULL, DEBUG_CONFIG | MODIFIABLE_CONFIG, server.active_defrag_enabled, 0, isValidActiveDefrag, NULL),
    createBoolConfig("syslog-enabled", NULL, IMMUTABLE_CONFIG, server.syslog_enabled, 0, NULL, NULL),
    createBoolConfig("cluster-enabled", NULL, IMMUTABLE_CONFIG, server.cluster_enabled, 0, NULL, NULL),
    createBoolConfig("appendonly", NULL, MODIFIABLE_CONFIG | DENY_LOADING_CONFIG, server.aof_enabled, 0, NULL, updateAppendonly),
    createBoolConfig("cluster-allow-reads-when-down", NULL, MODIFIABLE_CONFIG, server.cluster_allow_reads_when_down, 0, NULL, NULL),
    createBoolConfig("cluster-allow-pubsubshard-when-down", NULL, MODIFIABLE_CONFIG, server.cluster_allow_pubsubshard_when_down, 1, NULL, NULL),
    createBoolConfig("crash-log-enabled", NULL, MODIFIABLE_CONFIG, server.crashlog_enabled, 1, NULL, updateSighandlerEnabled),
    createBoolConfig("crash-memcheck-enabled", NULL, MODIFIABLE_CONFIG, server.memcheck_enabled, 1, NULL, NULL),
    createBoolConfig("use-exit-on-panic", NULL, MODIFIABLE_CONFIG | HIDDEN_CONFIG, server.use_exit_on_panic, 0, NULL, NULL),
    createBoolConfig("disable-thp", NULL, IMMUTABLE_CONFIG, server.disable_thp, 1, NULL, NULL),
    createBoolConfig("cluster-allow-replica-migration", NULL, MODIFIABLE_CONFIG, server.cluster_allow_replica_migration, 1, NULL, NULL),
    createBoolConfig("replica-announced", NULL, MODIFIABLE_CONFIG, server.replica_announced, 1, NULL, NULL),
    createBoolConfig("latency-tracking", NULL, MODIFIABLE_CONFIG, server.latency_tracking_enabled, 1, NULL, NULL),
    createBoolConfig("aof-disable-auto-gc", NULL, MODIFIABLE_CONFIG, server.aof_disable_auto_gc, 0, NULL, updateAofAutoGCEnabled),
    createBoolConfig("replica-ignore-disk-write-errors", NULL, MODIFIABLE_CONFIG, server.repl_ignore_disk_write_error, 0, NULL, NULL),

    /* String Configs */
    createStringConfig("aclfile", NULL, IMMUTABLE_CONFIG, ALLOW_EMPTY_STRING, server.acl_filename, "", NULL, NULL),
    createStringConfig("unixsocket", NULL, IMMUTABLE_CONFIG, EMPTY_STRING_IS_NULL, server.unixsocket, NULL, NULL, NULL),
    createStringConfig("pidfile", NULL, IMMUTABLE_CONFIG, EMPTY_STRING_IS_NULL, server.pidfile, NULL, NULL, NULL),
    createStringConfig("replica-announce-ip", "slave-announce-ip", MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.slave_announce_ip, NULL, NULL, NULL),
    createStringConfig("masteruser", NULL, MODIFIABLE_CONFIG | SENSITIVE_CONFIG, EMPTY_STRING_IS_NULL, server.masteruser, NULL, NULL, NULL),
    createStringConfig("cluster-announce-ip", NULL, MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.cluster_announce_ip, NULL, NULL, updateClusterIp),
    createStringConfig("cluster-config-file", NULL, IMMUTABLE_CONFIG, ALLOW_EMPTY_STRING, server.cluster_configfile, "nodes.conf", NULL, NULL),
    createStringConfig("cluster-announce-hostname", NULL, MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.cluster_announce_hostname, NULL, isValidAnnouncedHostname, updateClusterHostname),
    createStringConfig("syslog-ident", NULL, IMMUTABLE_CONFIG, ALLOW_EMPTY_STRING, server.syslog_ident, "redis", NULL, NULL),
    createStringConfig("dbfilename", NULL, MODIFIABLE_CONFIG | PROTECTED_CONFIG, ALLOW_EMPTY_STRING, server.rdb_filename, "dump.rdb", isValidDBfilename, NULL),
    createStringConfig("appendfilename", NULL, IMMUTABLE_CONFIG, ALLOW_EMPTY_STRING, server.aof_filename, "appendonly.aof", isValidAOFfilename, NULL),
    createStringConfig("appenddirname", NULL, IMMUTABLE_CONFIG, ALLOW_EMPTY_STRING, server.aof_dirname, "appendonlydir", isValidAOFdirname, NULL),
    createStringConfig("server_cpulist", NULL, IMMUTABLE_CONFIG, EMPTY_STRING_IS_NULL, server.server_cpulist, NULL, NULL, NULL),
    createStringConfig("bio_cpulist", NULL, IMMUTABLE_CONFIG, EMPTY_STRING_IS_NULL, server.bio_cpulist, NULL, NULL, NULL),
    createStringConfig("aof_rewrite_cpulist", NULL, IMMUTABLE_CONFIG, EMPTY_STRING_IS_NULL, server.aof_rewrite_cpulist, NULL, NULL, NULL),
    createStringConfig("bgsave_cpulist", NULL, IMMUTABLE_CONFIG, EMPTY_STRING_IS_NULL, server.bgsave_cpulist, NULL, NULL, NULL),
    createStringConfig("ignore-warnings", NULL, MODIFIABLE_CONFIG, ALLOW_EMPTY_STRING, server.ignore_warnings, "", NULL, NULL),
    createStringConfig("proc-title-template", NULL, MODIFIABLE_CONFIG, ALLOW_EMPTY_STRING, server.proc_title_template, CONFIG_DEFAULT_PROC_TITLE_TEMPLATE, isValidProcTitleTemplate, updateProcTitleTemplate),
    createStringConfig("bind-source-addr", NULL, MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.bind_source_addr, NULL, NULL, NULL),
    createStringConfig("logfile", NULL, IMMUTABLE_CONFIG, ALLOW_EMPTY_STRING, server.logfile, "", NULL, NULL),

    /* SDS Configs */
    createSDSConfig("masterauth", NULL, MODIFIABLE_CONFIG | SENSITIVE_CONFIG, EMPTY_STRING_IS_NULL, server.masterauth, NULL, NULL, NULL),
    createSDSConfig("requirepass", NULL, MODIFIABLE_CONFIG | SENSITIVE_CONFIG, EMPTY_STRING_IS_NULL, server.requirepass, NULL, NULL, updateRequirePass),

    /* Enum Configs */
    createEnumConfig("supervised", NULL, IMMUTABLE_CONFIG, supervised_mode_enum, server.supervised_mode, SUPERVISED_NONE, NULL, NULL),
    createEnumConfig("syslog-facility", NULL, IMMUTABLE_CONFIG, syslog_facility_enum, server.syslog_facility, LOG_LOCAL0, NULL, NULL),
    createEnumConfig("repl-diskless-load", NULL, DEBUG_CONFIG | MODIFIABLE_CONFIG | DENY_LOADING_CONFIG, repl_diskless_load_enum, server.repl_diskless_load, REPL_DISKLESS_LOAD_DISABLED, NULL, NULL),
    createEnumConfig("loglevel", NULL, MODIFIABLE_CONFIG, loglevel_enum, server.verbosity, LL_NOTICE, NULL, NULL),
    createEnumConfig("maxmemory-policy", NULL, MODIFIABLE_CONFIG, maxmemory_policy_enum, server.maxmemory_policy, MAXMEMORY_NO_EVICTION, NULL, NULL),
    createEnumConfig("appendfsync", NULL, MODIFIABLE_CONFIG, aof_fsync_enum, server.aof_fsync, AOF_FSYNC_EVERYSEC, NULL, NULL),
    createEnumConfig("oom-score-adj", NULL, MODIFIABLE_CONFIG, oom_score_adj_enum, server.oom_score_adj, OOM_SCORE_ADJ_NO, NULL, updateOOMScoreAdj),
    createEnumConfig("acl-pubsub-default", NULL, MODIFIABLE_CONFIG, acl_pubsub_default_enum, server.acl_pubsub_default, 0, NULL, NULL),
    createEnumConfig("sanitize-dump-payload", NULL, DEBUG_CONFIG | MODIFIABLE_CONFIG, sanitize_dump_payload_enum, server.sanitize_dump_payload, SANITIZE_DUMP_NO, NULL, NULL),
    createEnumConfig("enable-protected-configs", NULL, IMMUTABLE_CONFIG, protected_action_enum, server.enable_protected_configs, PROTECTED_ACTION_ALLOWED_NO, NULL, NULL),
    createEnumConfig("enable-debug-command", NULL, IMMUTABLE_CONFIG, protected_action_enum, server.enable_debug_cmd, PROTECTED_ACTION_ALLOWED_NO, NULL, NULL),
    createEnumConfig("enable-module-command", NULL, IMMUTABLE_CONFIG, protected_action_enum, server.enable_module_cmd, PROTECTED_ACTION_ALLOWED_NO, NULL, NULL),
    createEnumConfig("cluster-preferred-endpoint-type", NULL, MODIFIABLE_CONFIG, cluster_preferred_endpoint_type_enum, server.cluster_preferred_endpoint_type, CLUSTER_ENDPOINT_TYPE_IP, NULL, NULL),
    createEnumConfig("propagation-error-behavior", NULL, MODIFIABLE_CONFIG, propagation_error_behavior_enum, server.propagation_error_behavior, PROPAGATION_ERR_BEHAVIOR_IGNORE, NULL, NULL),
    createEnumConfig("shutdown-on-sigint", NULL, MODIFIABLE_CONFIG | MULTI_ARG_CONFIG, shutdown_on_sig_enum, server.shutdown_on_sigint, 0, isValidShutdownOnSigFlags, NULL),
    createEnumConfig("shutdown-on-sigterm", NULL, MODIFIABLE_CONFIG | MULTI_ARG_CONFIG, shutdown_on_sig_enum, server.shutdown_on_sigterm, 0, isValidShutdownOnSigFlags, NULL),

    /* Integer configs */
    /* name, alias, flags, lower, upper, config_addr, default, num_conf_flags, is_valid, apply */
    createIntConfig("databases", NULL, IMMUTABLE_CONFIG, 1, INT_MAX, server.dbnum, 16, INTEGER_CONFIG, NULL, NULL),
    createIntConfig("port", NULL, MODIFIABLE_CONFIG, 0, 65535, server.port, 6379, INTEGER_CONFIG, NULL, updatePort), /* TCP port. */
    createIntConfig("io-threads", NULL, DEBUG_CONFIG | IMMUTABLE_CONFIG, 1, 128, server.io_threads_num, 1, INTEGER_CONFIG, NULL, NULL), /* Single threaded by default */
    createIntConfig("auto-aof-rewrite-percentage", NULL, MODIFIABLE_CONFIG, 0, INT_MAX, server.aof_rewrite_perc, 100, INTEGER_CONFIG, NULL, NULL),
    createIntConfig("cluster-replica-validity-factor", "cluster-slave-validity-factor", MODIFIABLE_CONFIG, 0, INT_MAX, server.cluster_slave_validity_factor, 10, INTEGER_CONFIG, NULL, NULL), /* Slave max data age factor. */
    createIntConfig("list-max-listpack-size", "list-max-ziplist-size", MODIFIABLE_CONFIG, INT_MIN, INT_MAX, server.list_max_listpack_size, -2, INTEGER_CONFIG, NULL, NULL),
    createIntConfig("tcp-keepalive", NULL, MODIFIABLE_CONFIG, 0, INT_MAX, server.tcpkeepalive, 300, INTEGER_CONFIG, NULL, NULL),
    createIntConfig("cluster-migration-barrier", NULL, MODIFIABLE_CONFIG, 0, INT_MAX, server.cluster_migration_barrier, 1, INTEGER_CONFIG, NULL, NULL),
    createIntConfig("active-defrag-cycle-min", NULL, MODIFIABLE_CONFIG, 1, 99, server.active_defrag_cycle_min, 1, INTEGER_CONFIG, NULL, NULL), /* Default: 1% CPU min (at lower threshold) */
    createIntConfig("active-defrag-cycle-max", NULL, MODIFIABLE_CONFIG, 1, 99, server.active_defrag_cycle_max, 25, INTEGER_CONFIG, NULL, NULL), /* Default: 25% CPU max (at upper threshold) */
    createIntConfig("active-defrag-threshold-lower", NULL, MODIFIABLE_CONFIG, 0, 1000, server.active_defrag_threshold_lower, 10, INTEGER_CONFIG, NULL, NULL), /* Default: don't defrag when fragmentation is below 10% */
    createIntConfig("active-defrag-threshold-upper", NULL, MODIFIABLE_CONFIG, 0, 1000, server.active_defrag_threshold_upper, 100, INTEGER_CONFIG, NULL, NULL), /* Default: maximum defrag force at 100% fragmentation */
    createIntConfig("lfu-log-factor", NULL, MODIFIABLE_CONFIG, 0, INT_MAX, server.lfu_log_factor, 10, INTEGER_CONFIG, NULL, NULL),
    createIntConfig("lfu-decay-time", NULL, MODIFIABLE_CONFIG, 0, INT_MAX, server.lfu_decay_time, 1, INTEGER_CONFIG, NULL, NULL),
    createIntConfig("replica-priority", "slave-priority", MODIFIABLE_CONFIG, 0, INT_MAX, server.slave_priority, 100, INTEGER_CONFIG, NULL, NULL),
    createIntConfig("repl-diskless-sync-delay", NULL, MODIFIABLE_CONFIG, 0, INT_MAX, server.repl_diskless_sync_delay, 5, INTEGER_CONFIG, NULL, NULL),
    createIntConfig("maxmemory-samples", NULL, MODIFIABLE_CONFIG, 1, INT_MAX, server.maxmemory_samples, 5, INTEGER_CONFIG, NULL, NULL),
    createIntConfig("maxmemory-eviction-tenacity", NULL, MODIFIABLE_CONFIG, 0, 100, server.maxmemory_eviction_tenacity, 10, INTEGER_CONFIG, NULL, NULL),
    createIntConfig("timeout", NULL, MODIFIABLE_CONFIG, 0, INT_MAX, server.maxidletime, 0, INTEGER_CONFIG, NULL, NULL), /* Default client timeout: infinite */
    createIntConfig("replica-announce-port", "slave-announce-port", MODIFIABLE_CONFIG, 0, 65535, server.slave_announce_port, 0, INTEGER_CONFIG, NULL, NULL),
    createIntConfig("tcp-backlog", NULL, IMMUTABLE_CONFIG, 0, INT_MAX, server.tcp_backlog, 511, INTEGER_CONFIG, NULL, NULL), /* TCP listen backlog. */
    createIntConfig("cluster-port", NULL, IMMUTABLE_CONFIG, 0, 65535, server.cluster_port, 0, INTEGER_CONFIG, NULL, NULL),    
    createIntConfig("cluster-announce-bus-port", NULL, MODIFIABLE_CONFIG, 0, 65535, server.cluster_announce_bus_port, 0, INTEGER_CONFIG, NULL, updateClusterAnnouncedPort), /* Default: Use +10000 offset. */
    createIntConfig("cluster-announce-port", NULL, MODIFIABLE_CONFIG, 0, 65535, server.cluster_announce_port, 0, INTEGER_CONFIG, NULL, updateClusterAnnouncedPort), /* Use server.port */
    createIntConfig("cluster-announce-tls-port", NULL, MODIFIABLE_CONFIG, 0, 65535, server.cluster_announce_tls_port, 0, INTEGER_CONFIG, NULL, updateClusterAnnouncedPort), /* Use server.tls_port */
    createIntConfig("repl-timeout", NULL, MODIFIABLE_CONFIG, 1, INT_MAX, server.repl_timeout, 60, INTEGER_CONFIG, NULL, NULL),
    createIntConfig("repl-ping-replica-period", "repl-ping-slave-period", MODIFIABLE_CONFIG, 1, INT_MAX, server.repl_ping_slave_period, 10, INTEGER_CONFIG, NULL, NULL),
    createIntConfig("list-compress-depth", NULL, DEBUG_CONFIG | MODIFIABLE_CONFIG, 0, INT_MAX, server.list_compress_depth, 0, INTEGER_CONFIG, NULL, NULL),
    createIntConfig("rdb-key-save-delay", NULL, MODIFIABLE_CONFIG | HIDDEN_CONFIG, INT_MIN, INT_MAX, server.rdb_key_save_delay, 0, INTEGER_CONFIG, NULL, NULL),
    createIntConfig("key-load-delay", NULL, MODIFIABLE_CONFIG | HIDDEN_CONFIG, INT_MIN, INT_MAX, server.key_load_delay, 0, INTEGER_CONFIG, NULL, NULL),
    createIntConfig("active-expire-effort", NULL, MODIFIABLE_CONFIG, 1, 10, server.active_expire_effort, 1, INTEGER_CONFIG, NULL, NULL), /* From 1 to 10. */
    createIntConfig("hz", NULL, MODIFIABLE_CONFIG, 0, INT_MAX, server.config_hz, CONFIG_DEFAULT_HZ, INTEGER_CONFIG, NULL, updateHZ),
    createIntConfig("min-replicas-to-write", "min-slaves-to-write", MODIFIABLE_CONFIG, 0, INT_MAX, server.repl_min_slaves_to_write, 0, INTEGER_CONFIG, NULL, updateGoodSlaves),
    createIntConfig("min-replicas-max-lag", "min-slaves-max-lag", MODIFIABLE_CONFIG, 0, INT_MAX, server.repl_min_slaves_max_lag, 10, INTEGER_CONFIG, NULL, updateGoodSlaves),
    createIntConfig("watchdog-period", NULL, MODIFIABLE_CONFIG | HIDDEN_CONFIG, 0, INT_MAX, server.watchdog_period, 0, INTEGER_CONFIG, NULL, updateWatchdogPeriod),
    createIntConfig("shutdown-timeout", NULL, MODIFIABLE_CONFIG, 0, INT_MAX, server.shutdown_timeout, 10, INTEGER_CONFIG, NULL, NULL),
    createIntConfig("repl-diskless-sync-max-replicas", NULL, MODIFIABLE_CONFIG, 0, INT_MAX, server.repl_diskless_sync_max_replicas, 0, INTEGER_CONFIG, NULL, NULL),

    /* Unsigned int configs */
    createUIntConfig("maxclients", NULL, MODIFIABLE_CONFIG, 1, UINT_MAX, server.maxclients, 10000, INTEGER_CONFIG, NULL, updateMaxclients),
    createUIntConfig("unixsocketperm", NULL, IMMUTABLE_CONFIG, 0, 0777, server.unixsocketperm, 0, OCTAL_CONFIG, NULL, NULL),
    createUIntConfig("socket-mark-id", NULL, IMMUTABLE_CONFIG, 0, UINT_MAX, server.socket_mark_id, 0, INTEGER_CONFIG, NULL, NULL),

    /* Unsigned Long configs */
    createULongConfig("active-defrag-max-scan-fields", NULL, MODIFIABLE_CONFIG, 1, LONG_MAX, server.active_defrag_max_scan_fields, 1000, INTEGER_CONFIG, NULL, NULL), /* Default: keys with more than 1000 fields will be processed separately */
    createULongConfig("slowlog-max-len", NULL, MODIFIABLE_CONFIG, 0, LONG_MAX, server.slowlog_max_len, 128, INTEGER_CONFIG, NULL, NULL),
    createULongConfig("acllog-max-len", NULL, MODIFIABLE_CONFIG, 0, LONG_MAX, server.acllog_max_len, 128, INTEGER_CONFIG, NULL, NULL),

    /* Long Long configs */
    createLongLongConfig("busy-reply-threshold", "lua-time-limit", MODIFIABLE_CONFIG, 0, LONG_MAX, server.busy_reply_threshold, 5000, INTEGER_CONFIG, NULL, NULL),/* milliseconds */
    createLongLongConfig("cluster-node-timeout", NULL, MODIFIABLE_CONFIG, 0, LLONG_MAX, server.cluster_node_timeout, 15000, INTEGER_CONFIG, NULL, NULL),
    createLongLongConfig("slowlog-log-slower-than", NULL, MODIFIABLE_CONFIG, -1, LLONG_MAX, server.slowlog_log_slower_than, 10000, INTEGER_CONFIG, NULL, NULL),
    createLongLongConfig("latency-monitor-threshold", NULL, MODIFIABLE_CONFIG, 0, LLONG_MAX, server.latency_monitor_threshold, 0, INTEGER_CONFIG, NULL, NULL),
    createLongLongConfig("proto-max-bulk-len", NULL, DEBUG_CONFIG | MODIFIABLE_CONFIG, 1024*1024, LONG_MAX, server.proto_max_bulk_len, 512ll*1024*1024, MEMORY_CONFIG, NULL, NULL), /* Bulk request max size */
    createLongLongConfig("stream-node-max-entries", NULL, MODIFIABLE_CONFIG, 0, LLONG_MAX, server.stream_node_max_entries, 100, INTEGER_CONFIG, NULL, NULL),
    createLongLongConfig("repl-backlog-size", NULL, MODIFIABLE_CONFIG, 1, LLONG_MAX, server.repl_backlog_size, 1024*1024, MEMORY_CONFIG, NULL, updateReplBacklogSize), /* Default: 1mb */

    /* Unsigned Long Long configs */
    createULongLongConfig("maxmemory", NULL, MODIFIABLE_CONFIG, 0, ULLONG_MAX, server.maxmemory, 0, MEMORY_CONFIG, NULL, updateMaxmemory),
    createULongLongConfig("cluster-link-sendbuf-limit", NULL, MODIFIABLE_CONFIG, 0, ULLONG_MAX, server.cluster_link_sendbuf_limit_bytes, 0, MEMORY_CONFIG, NULL, NULL),

    /* Size_t configs */
    createSizeTConfig("hash-max-listpack-entries", "hash-max-ziplist-entries", MODIFIABLE_CONFIG, 0, LONG_MAX, server.hash_max_listpack_entries, 512, INTEGER_CONFIG, NULL, NULL),
    createSizeTConfig("set-max-intset-entries", NULL, MODIFIABLE_CONFIG, 0, LONG_MAX, server.set_max_intset_entries, 512, INTEGER_CONFIG, NULL, NULL),
    createSizeTConfig("zset-max-listpack-entries", "zset-max-ziplist-entries", MODIFIABLE_CONFIG, 0, LONG_MAX, server.zset_max_listpack_entries, 128, INTEGER_CONFIG, NULL, NULL),
    createSizeTConfig("active-defrag-ignore-bytes", NULL, MODIFIABLE_CONFIG, 1, LLONG_MAX, server.active_defrag_ignore_bytes, 100<<20, MEMORY_CONFIG, NULL, NULL), /* Default: don't defrag if frag overhead is below 100mb */
    createSizeTConfig("hash-max-listpack-value", "hash-max-ziplist-value", MODIFIABLE_CONFIG, 0, LONG_MAX, server.hash_max_listpack_value, 64, MEMORY_CONFIG, NULL, NULL),
    createSizeTConfig("stream-node-max-bytes", NULL, MODIFIABLE_CONFIG, 0, LONG_MAX, server.stream_node_max_bytes, 4096, MEMORY_CONFIG, NULL, NULL),
    createSizeTConfig("zset-max-listpack-value", "zset-max-ziplist-value", MODIFIABLE_CONFIG, 0, LONG_MAX, server.zset_max_listpack_value, 64, MEMORY_CONFIG, NULL, NULL),
    createSizeTConfig("hll-sparse-max-bytes", NULL, MODIFIABLE_CONFIG, 0, LONG_MAX, server.hll_sparse_max_bytes, 3000, MEMORY_CONFIG, NULL, NULL),
    createSizeTConfig("tracking-table-max-keys", NULL, MODIFIABLE_CONFIG, 0, LONG_MAX, server.tracking_table_max_keys, 1000000, INTEGER_CONFIG, NULL, NULL), /* Default: 1 million keys max. */
    createSizeTConfig("client-query-buffer-limit", NULL, DEBUG_CONFIG | MODIFIABLE_CONFIG, 1024*1024, LONG_MAX, server.client_max_querybuf_len, 1024*1024*1024, MEMORY_CONFIG, NULL, NULL), /* Default: 1GB max query buffer. */
    createSSizeTConfig("maxmemory-clients", NULL, MODIFIABLE_CONFIG, -100, SSIZE_MAX, server.maxmemory_clients, 0, MEMORY_CONFIG | PERCENT_CONFIG, NULL, applyClientMaxMemoryUsage),

    /* Other configs */
    createTimeTConfig("repl-backlog-ttl", NULL, MODIFIABLE_CONFIG, 0, LONG_MAX, server.repl_backlog_time_limit, 60*60, INTEGER_CONFIG, NULL, NULL), /* Default: 1 hour */
    createOffTConfig("auto-aof-rewrite-min-size", NULL, MODIFIABLE_CONFIG, 0, LLONG_MAX, server.aof_rewrite_min_size, 64*1024*1024, MEMORY_CONFIG, NULL, NULL),
    createOffTConfig("loading-process-events-interval-bytes", NULL, MODIFIABLE_CONFIG | HIDDEN_CONFIG, 1024, INT_MAX, server.loading_process_events_interval_bytes, 1024*1024*2, INTEGER_CONFIG, NULL, NULL),

#ifdef USE_OPENSSL
    createIntConfig("tls-port", NULL, MODIFIABLE_CONFIG, 0, 65535, server.tls_port, 0, INTEGER_CONFIG, NULL, applyTLSPort), /* TCP port. */
    createIntConfig("tls-session-cache-size", NULL, MODIFIABLE_CONFIG, 0, INT_MAX, server.tls_ctx_config.session_cache_size, 20*1024, INTEGER_CONFIG, NULL, applyTlsCfg),
    createIntConfig("tls-session-cache-timeout", NULL, MODIFIABLE_CONFIG, 0, INT_MAX, server.tls_ctx_config.session_cache_timeout, 300, INTEGER_CONFIG, NULL, applyTlsCfg),
    createBoolConfig("tls-cluster", NULL, MODIFIABLE_CONFIG, server.tls_cluster, 0, NULL, applyTlsCfg),
    createBoolConfig("tls-replication", NULL, MODIFIABLE_CONFIG, server.tls_replication, 0, NULL, applyTlsCfg),
    createEnumConfig("tls-auth-clients", NULL, MODIFIABLE_CONFIG, tls_auth_clients_enum, server.tls_auth_clients, TLS_CLIENT_AUTH_YES, NULL, NULL),
    createBoolConfig("tls-prefer-server-ciphers", NULL, MODIFIABLE_CONFIG, server.tls_ctx_config.prefer_server_ciphers, 0, NULL, applyTlsCfg),
    createBoolConfig("tls-session-caching", NULL, MODIFIABLE_CONFIG, server.tls_ctx_config.session_caching, 1, NULL, applyTlsCfg),
    createStringConfig("tls-cert-file", NULL, VOLATILE_CONFIG | MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.tls_ctx_config.cert_file, NULL, NULL, applyTlsCfg),
    createStringConfig("tls-key-file", NULL, VOLATILE_CONFIG | MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.tls_ctx_config.key_file, NULL, NULL, applyTlsCfg),
    createStringConfig("tls-key-file-pass", NULL, MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.tls_ctx_config.key_file_pass, NULL, NULL, applyTlsCfg),
    createStringConfig("tls-client-cert-file", NULL, VOLATILE_CONFIG | MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.tls_ctx_config.client_cert_file, NULL, NULL, applyTlsCfg),
    createStringConfig("tls-client-key-file", NULL, VOLATILE_CONFIG | MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.tls_ctx_config.client_key_file, NULL, NULL, applyTlsCfg),
    createStringConfig("tls-client-key-file-pass", NULL, MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.tls_ctx_config.client_key_file_pass, NULL, NULL, applyTlsCfg),
    createStringConfig("tls-dh-params-file", NULL, VOLATILE_CONFIG | MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.tls_ctx_config.dh_params_file, NULL, NULL, applyTlsCfg),
    createStringConfig("tls-ca-cert-file", NULL, VOLATILE_CONFIG | MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.tls_ctx_config.ca_cert_file, NULL, NULL, applyTlsCfg),
    createStringConfig("tls-ca-cert-dir", NULL, VOLATILE_CONFIG | MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.tls_ctx_config.ca_cert_dir, NULL, NULL, applyTlsCfg),
    createStringConfig("tls-protocols", NULL, MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.tls_ctx_config.protocols, NULL, NULL, applyTlsCfg),
    createStringConfig("tls-ciphers", NULL, MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.tls_ctx_config.ciphers, NULL, NULL, applyTlsCfg),
    createStringConfig("tls-ciphersuites", NULL, MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.tls_ctx_config.ciphersuites, NULL, NULL, applyTlsCfg),
#endif

    /* Special configs */
    createSpecialConfig("dir", NULL, MODIFIABLE_CONFIG | PROTECTED_CONFIG | DENY_LOADING_CONFIG, setConfigDirOption, getConfigDirOption, rewriteConfigDirOption, NULL),
    createSpecialConfig("save", NULL, MODIFIABLE_CONFIG | MULTI_ARG_CONFIG, setConfigSaveOption, getConfigSaveOption, rewriteConfigSaveOption, NULL),
    createSpecialConfig("client-output-buffer-limit", NULL, MODIFIABLE_CONFIG | MULTI_ARG_CONFIG, setConfigClientOutputBufferLimitOption, getConfigClientOutputBufferLimitOption, rewriteConfigClientOutputBufferLimitOption, NULL),
    createSpecialConfig("oom-score-adj-values", NULL, MODIFIABLE_CONFIG | MULTI_ARG_CONFIG, setConfigOOMScoreAdjValuesOption, getConfigOOMScoreAdjValuesOption, rewriteConfigOOMScoreAdjValuesOption, updateOOMScoreAdj),
    createSpecialConfig("notify-keyspace-events", NULL, MODIFIABLE_CONFIG, setConfigNotifyKeyspaceEventsOption, getConfigNotifyKeyspaceEventsOption, rewriteConfigNotifyKeyspaceEventsOption, NULL),
    createSpecialConfig("bind", NULL, MODIFIABLE_CONFIG | MULTI_ARG_CONFIG, setConfigBindOption, getConfigBindOption, rewriteConfigBindOption, applyBind),
    createSpecialConfig("replicaof", "slaveof", IMMUTABLE_CONFIG | MULTI_ARG_CONFIG, setConfigReplicaOfOption, getConfigReplicaOfOption, rewriteConfigReplicaOfOption, NULL),
    createSpecialConfig("latency-tracking-info-percentiles", NULL, MODIFIABLE_CONFIG | MULTI_ARG_CONFIG, setConfigLatencyTrackingInfoPercentilesOutputOption, getConfigLatencyTrackingInfoPercentilesOutputOption, rewriteConfigLatencyTrackingInfoPercentilesOutputOption, NULL),

    /* NULL Terminator, this is dropped when we convert to the runtime array. */
    {NULL}
};

存在这么多默认配置项，以及用户可以自定义的配置项。那么，你有没有想过 Redis 是如何初始化配置信息的呢？

Redis初始化配置信息过程

Redis Server服务端启动之后，存在一个struct redisServer类型的全局变量server，其中几乎存储着整个Redis服务运行所需要的数据信息，Redis配置项中的众多字段信息也包含在其结构体中。例如：监听的端口号、地址等信息。

从上图可知，程序启动时由main()方法(代码位置：src/server.c)进入，在启动并正式对外服务之前会进行配置信息的解析。主要包含2部分处理逻辑：

  1. 使用默认配置项初始化
  2. 存在自定义配置文件，则解析配置文件并使用自定义配置覆盖默认配置项

在整个Redis服务运行过程中，除了在启动之前使用默认配置项+解析配置文件的静态配置方式之外，还可以使用命令 CONFIG SET config_name config_value 的动态配置形式对配置项进行更新。