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MEMCACHED(1)                                                                                    MEMCACHED(1)



NAME
       memcached - high-performance memory object caching system

SYNOPSIS
       memcached [options]

DESCRIPTION
       This manual page documents briefly the memcached memory object caching daemon.

       memcached  is  a flexible memory object caching daemon designed to alleviate database load in dynamic
       web applications by storing objects in memory.  It's based on libevent to scale to any  size  needed,
       and is specifically optimized to avoid swapping and always use non-blocking I/O.

OPTIONS
       These programs follow the usual GNU command line syntax. A summary of options is included below.

       -s <file>
              Unix socket path to listen on (disables network support).

       -a <perms>
              Permissions (in octal format) for Unix socket created with -s option.

       -l <ip_addr>
              Listen on <ip_addr>; default to INDRR_ANY. This is an important option to consider as there is
              no other way to secure the installation. Binding to an internal or firewalled  network  inter-face interface
              face is suggested.

       -d     Run memcached as a daemon.

       -u <username>
              Assume the identity of <username> (only when run as root).

       -m <num>
              Use <num> MB memory max to use for object storage; the default is 64 megabytes.

       -c <num>
              Use <num> max simultaneous connections; the default is 1024.

       -k     Lock  down all paged memory. This is a somewhat dangerous option with large caches, so consult
              the README and memcached homepage for configuration suggestions.

       -p <num>
              Listen on TCP port <num>, the default is port 11211.

       -U <num>
              Listen on UDP port <num>, the default is port 11211, 0 is off.

       -M     Disable automatic removal of items from the cache when out of memory.  Additions will  not  be
              possible until adequate space is freed up.

       -r     Raise the core file size limit to the maximum allowable.

       -f <factor>
              Use  <factor> as the multiplier for computing the sizes of memory chunks that items are stored
              in. A lower value may result in less wasted memory depending on the  total  amount  of  memory
              available and the distribution of item sizes.  The default is 1.25.

       -n <size>
              Allocate  a  minimum of <size> bytes for the item key, value, and flags. The default is 48. If
              you have a lot of small keys and values, you can get a significant memory efficiency gain with
              a  lower  value. If you use a high chunk growth factor (-f option), on the other hand, you may
              want to increase the size to allow a bigger percentage of  your  items  to  fit  in  the  most
              densely packed (smallest) chunks.

       -h     Show the version of memcached and a summary of options.

       -v     Be verbose during the event loop; print out errors and warnings.

       -vv    Be even more verbose; same as -v but also print client commands and responses.

       -i     Print memcached and libevent licenses.

       -P <filename>
              Print pidfile to <filename>, only used under -d option.

       -t <threads>
              Number  of threads to use to process incoming requests. This option is only meaningful if mem-cached memcached
              cached was compiled with thread support enabled. It is typically not useful to set this higher
              than the number of CPU cores on the memcached server. The default is 4.

       -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.

       -L     Try to use large memory pages (if available). Increasing the memory page size could reduce the
              number  of  TLB  misses  and improve the performance. In order to get large pages from the OS,
              memcached will allocate the total item-cache in one large chunk. Only available  if  supported
              on your OS.

LICENSE
       The  memcached  daemon  is copyright Danga Interactive and is distributed under the BSD license. Note
       that daemon clients are licensed separately.

SEE ALSO
       The README file that comes with memcached
       http://www.danga.com/memcached

AUTHOR
       The memcached  daemon  was  written  by  Anatoly  Vorobey  <mellon@pobox.com>  and  Brad  Fitzpatrick
       <brad@danga.com> and the rest of the crew of Danga Interactive http://www.danga.com



                                               April 11, 2005                                   MEMCACHED(1)