/usr/bin/memcached

memcached 1.6.45
-p, --port=<num>          TCP port to listen on (default: 11211)
-U, --udp-port=<num>      UDP port to listen on (default: 0, off)
-s, --unix-socket=<file>  UNIX socket to listen on (disables network support)
-a, --unix-mask=<mask>    access mask for UNIX socket, in octal (default: 700)
-A, --enable-shutdown     enable ascii "shutdown" command
-l, --listen=<addr>       interface to listen on (default: INADDR_ANY)
                          can specify multiple comma separated listeners configured with different protocols
                          format: proto[<protcol>]:tag[<name>]:ip:port
                          i.e -l proto[binary]:tag[services]:127.0.0.1:11211,proto[ascii]:tag_tools_:127.0.0.1:11212
                          if TLS/SSL is enabled, 'notls', 'btls', 'mtls' prefix can be used to
                          specify for specific listeners no tls, basic tls, or peer-auth tls (i.e -l mtls:proto[ascii]:tag_tools_:127.0.0.1:11212
-d, --daemon              run as a daemon
-r, --enable-coredumps    maximize core file limit
-u, --user=<user>         assume identity of <username> (only when run as root)
-m, --memory-limit=<num>  item memory in megabytes (default: 64)
-M, --disable-evictions   return error on memory exhausted instead of evicting
-c, --conn-limit=<num>    max simultaneous connections (default: 1024)
-k, --lock-memory         lock down all paged memory
-v, --verbose             verbose (print errors/warnings while in event loop)
-vv                       very verbose (also print client commands/responses)
-vvv                      extremely verbose (internal state transitions)
-h, --help                print this help and exit
-i, --license             print memcached and libevent license
-V, --version             print version and exit
-P, --pidfile=<file>      save PID in <file>, only used with -d option
-f, --slab-growth-factor=<num> chunk size growth factor (default: 1.25)
-n, --slab-min-size=<bytes> min space used for key+value+flags (default: 48)
-L, --enable-largepages  try to use large memory pages (if available)
-D <char>     Use <char> as the delimiter between key prefixes and IDs.
              This is used for per-prefix stats reporting. The default is
              ":" (colon). If this option is specified, stats collection
              is turned on automatically; if not, then it may be turned on
              by sending the "stats detail on" command to the server.
-t, --threads=<num>       number of threads to use (default: 4)
-R, --max-reqs-per-event  maximum number of requests per event, limits the
                          requests processed per connection to prevent
                          starvation (default: 20)
-C, --disable-cas         disable use of CAS
-b, --listen-backlog=<num> set the backlog queue limit (default: 1024)
-B, --protocol=<name>     protocol - one of ascii, binary, or auto (default: auto-negotiate)
-I, --max-item-size=<num> adjusts max item size
                          (default: 1m, min: 1k, max: 1024m)
-S, --enable-sasl         turn on Sasl authentication
-F, --disable-flush-all   disable flush_all command
-X, --disable-dumping     disable stats cachedump, stats detail, and lru_crawler metadump
-W  --disable-watch       disable watch commands (live logging)
-Y, --auth-file=<file>    (EXPERIMENTAL) enable ASCII protocol authentication. format:
                          user:pass\nuser2:pass2\n
-e, --memory-file=<file>  (EXPERIMENTAL) mmap a file for item memory.
                          use only in ram disks or persistent memory mounts!
                          enables restartable cache (stop with SIGUSR1)
-Z, --enable-ssl          enable TLS/SSL
-o, --extended            comma separated list of extended options
                          most options have a 'no_' prefix to disable
   - maxconns_fast:       immediately close new connections after limit (default: enabled)
   - hashpower:           an integer multiplier for how large the hash
                          table should be. normally grows at runtime. (default starts at: 0)
                          set based on "STAT hash_power_level"
   - tail_repair_time:    time in seconds for how long to wait before
                          forcefully killing LRU tail item.
                          disabled by default; very dangerous option.
   - hash_algorithm:      the hash table algorithm
                          default is murmur3 hash.
                          options: jenkins, murmur3, xxh3
   - no_lru_crawler:      disable LRU Crawler background thread.
   - lru_crawler_sleep:   microseconds to sleep between items
                          default is 100.
   - lru_crawler_tocrawl: max items to crawl per slab per run
                          default is 0 (unlimited)
   - read_buf_mem_limit:  limit in megabytes for connection read/response buffers.
                          do not adjust unless you have high (20k+) conn. limits.
                          0 means unlimited (default: 0)
   - no_lru_maintainer:   disable new LRU system + background thread.
   - hot_lru_pct:         pct of slab memory to reserve for hot lru.
                          (requires lru_maintainer, default pct: 20)
   - warm_lru_pct:        pct of slab memory to reserve for warm lru.
                          (requires lru_maintainer, default pct: 40)
   - hot_max_factor:      items idle > cold lru age * drop from hot lru. (default: 0.20)
   - warm_max_factor:     items idle > cold lru age * this drop from warm. (default: 2.00)
   - temporary_ttl:       TTL's below get separate LRU, can't be evicted.
                          (requires lru_maintainer, default: 61)
   - idle_timeout:        timeout for idle connections. (default: 0, no timeout)
   - slab_chunk_max:      (EXPERIMENTAL) maximum slab size in kilobytes. use extreme care. (default: 512)
   - watcher_logbuf_size: size in kilobytes of per-watcher write buffer. (default: 256)
   - worker_logbuf_size:  size in kilobytes of per-worker-thread buffer
                          read by background thread, then written to watchers. (default: 64)
   - track_sizes:         enable dynamic reports for 'stats sizes' command.
                          note that counts for each size are approximate.
   - no_hashexpand:       disables hash table expansion (dangerous)
   - modern:              enables options which will be default in future.
                          currently: nothing
   - no_modern:           uses defaults of previous major version (1.4.x)
   - drop_privileges:     enable dropping extra syscall privileges
   - no_drop_privileges:  disable drop_privileges in case it causes issues with
                          some customisation.
                          (default is no_drop_privileges)
   - sock_cookie_id:      attributes an ID to a socket for ip filtering/firewalls

   - External storage (ext_*) related options (see: https://memcached.org/extstore)
   - ext_path:            file to write to for external storage.
                          ie: ext_path=/mnt/d1/extstore:1G
   - ext_page_size:       size in megabytes of storage pages. (default: 64)
   - ext_wbuf_size:       size in megabytes of page write buffers. (default: 4)
   - ext_threads:         number of IO threads to run. (default: 1)
   - ext_item_size:       store items larger than this (bytes, default 512)
   - ext_item_age:        store items idle at least this long (seconds, default: no age limit)
   - ext_low_ttl:         consider TTLs lower than this specially (default: 0)
   - ext_drop_unread:     don't re-write unread values during compaction (default: disabled)
   - ext_recache_rate:    recache an item every N accesses (default: 2000)
   - ext_compact_under:   compact when fewer than this many free pages
                          (default: 1 percent of the assigned storage)
   - ext_drop_under:      drop COLD items when fewer than this many free pages
                          (default: 1/4th of the assigned storage)
   - ext_max_frag:        only defrag pages if they are less full than this pct-wise (default: 0.80)
   - ext_max_sleep:       max sleep time of background threads in us (default: 1000000)
   - slab_automove_freeratio: ratio of memory to hold free as buffer.
                          (see doc/storage.txt for more info, default: 0.010)
   - ssl_chain_cert:      certificate chain file in PEM format
   - ssl_key:             private key, if not part of the -ssl_chain_cert
   - ssl_keyformat:       private key format (PEM, DER or ENGINE) (default: PEM)
   - ssl_verify_mode:     peer certificate verification mode, default is 0(None).
                          valid values are 0(None), 1(Request), 2(Require)
                          or 3(Once)
   - ssl_ciphers:         specify cipher list to be used
   - ssl_ca_cert:         PEM format file of acceptable client CA's
   - ssl_wbuf_size:       size in kilobytes of per-connection SSL output buffer
                          (default: 16)
   - ssl_session_cache:   enable server-side SSL session cache, to support session
                          resumption
   - ssl_kernel_tls:      enable kernel TLS offload
   - ssl_min_version:     minimum protocol version to accept (default: tlsv1.2)
                          valid values are 0(tlsv1.0), 1(tlsv1.1), 2(tlsv1.2), or 3(tlsv1.3).
-N, --napi_ids            number of napi ids. see doc/napi_ids.txt for more details