Use active-replica cautiously — it enables optimistic write conflicts. | Directive | Default | Description | |-----------|---------|-------------| | maxclients | 10000 | Max simultaneous client connections. | | client-output-buffer-limit normal | 0 0 0 | Normal clients: hard, soft, seconds. | | client-output-buffer-limit replica | 256mb 64mb 60 | Replica clients. | | client-output-buffer-limit pubsub | 32mb 8mb 60 | Pub/sub clients. | 12. Lazy Freeing (Non-Blocking Deletion) KeyDB supports non-blocking deletes for large keys.
Use both RDB (for backups) and AOF (for durability). Set appendfsync everysec for balance. 7. Security Directives | Directive | Default | Description | |-----------|---------|-------------| | requirepass | (empty) | Password for AUTH command. | | masterauth | (empty) | Password for replica → master auth. | | rename-command | (none) | Disable or rename dangerous commands (e.g., FLUSHALL ). | | aclfile | (none) | External ACL configuration file (KeyDB 6+). | keydb.cfg
For production, bind to specific internal IPs, enable keepalive, and set a reasonable timeout. 4. Threading Model (KeyDB-Specific) This is the core differentiator from Redis. | | client-output-buffer-limit replica | 256mb 64mb 60
| Directive | Default | Description | |-----------|---------|-------------| | lazyfree-lazy-eviction | no | Use async free on eviction. | | lazyfree-lazy-expire | no | Use async free on key expiry. | | lazyfree-lazy-server-del | no | Replace DEL with UNLINK . | | replica-lazy-flush | no | Async flush on replica sync. | | Directive | Default | Description | |-----------|---------|-------------| | slowlog-log-slower-than | 10000 | Microsecond threshold. 0 = all, -1 = off. | | slowlog-max-len | 128 | Max number of slow entries to keep. | 14. Advanced Data Structure Tuning | Directive | Default | Description | |-----------|---------|-------------| | hash-max-ziplist-entries | 512 | Convert hash to ziplist under this many entries. | | hash-max-ziplist-value | 64 | Max size of hash entry value for ziplist (bytes). | | list-max-ziplist-size | -2 | List quicklist ziplist size. | | set-max-intset-entries | 512 | Max integer set entries before conversion. | | zset-max-ziplist-entries | 128 | Max sorted set entries for ziplist. | | zset-max-ziplist-value | 64 | Max value size for ziplist. | | stream-node-max-bytes | 4096 | Max bytes per stream listpack node. | | stream-node-max-entries | 100 | Max entries per stream node. | bind to specific internal IPs
Do not use rename-command to obfuscate commands — use ACLs. Always set a requirepass in production. 8. Memory Management | Directive | Default | Description | |-----------|---------|-------------| | maxmemory | 0 | Max memory in bytes. 0 = unlimited. | | maxmemory-policy | noeviction | Eviction policy: volatile-lru , allkeys-lru , volatile-random , allkeys-random , volatile-ttl , noeviction . | | maxmemory-samples | 5 | Number of keys to sample for LRU/TTL. | | active-defrag | no | Enable online defragmentation. | | active-defrag-threshold-lower | 10 | Fragmentation % to start. | | active-defrag-threshold-upper | 100 | Fragmentation % to force. | | active-defrag-cycle-min | 5 | Minimum CPU % for defrag. | | active-defrag-cycle-max | 75 | Maximum CPU % for defrag. |
