NAME

       memcachedb - persistence-enabled variant of memcached

SYNOPSIS

       memcachedb [OPTIONS]

DESCRIPTION

       MemcacheDB (pronounced mem-cash-dee-bee) is a persistence-enabled variant of the memcached
       distributed key-value storage system. It is NOT a cache solution, but rather a  persistent
       storage engine for fast and reliable key-value based object storage and retrieval.

       It  conforms  to the memcache protocol, which means that memcached clients can connect and
       use the persistent key-value store transparently. It also provides reliability  and  high-
       availability  through  its transaction and replication support, courtesy of its BerkeleyDB
       storage backend.

OPTIONS

       -p <num>
              TCP port to listen on  (default: 21201)

       -U <num>
              UDP port to listen on (default: 0, off)

       -s <file>
              UNIX Domain Socket path to listen on (disables network support)

       -a <mask>
              Access mask for unix socket, in octal (default: 0700)

       -l <ip_addr>
              Interface to listen on (default: INADRR_ANY)

       -d     Run as a daemon

       -r     Maximize core file limit

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

       -c <num>
              Maximum simultaneous connections (default: 4096)

       -b <num>
              Item size smaller than <num> bytes will use fast memory allocation  (default:  2048
              bytes)

       -v     Verbose (print errors/warnings while in event loop)

       -vv    Very verbose (also print client commands/reponses)

       -h     Print brief usage instructions and exit

       -i     Print complete copyright and license information

       -P <file>
              Save process ID in <file> (only used with the -d option)

       -t <num>
              Number of threads to use (default: 4)

   Berkeley DB Options
       -m <num>
              In-memory cache size of BerkeleyDB in megabytes (default: 256MB)

       -A <num>
              Underlying page size in bytes (default: 4096, range: 512B-64KB, power-of-two)

       -f <file>
              Filename of database (default: data.db)

       -H <dir>
              Environment HOME of database (default: /data1/memcachedb)

       -G <dir>
              Log directory of database (default: same as Environment HOME, see -H)

       -B <db_type>
              Type of database, options are: 'btree' or 'hash' (default: btree)

       -L <num>
              Log buffer size in kBytes (default: 4096kB)

       -C <num>
              Perform a checkpoint every <num> seconds (0 to disable, default: 300 seconds)

       -T <num>
              Do memp_trickle every <num> seconds (0 to disable, default: 30 seconds)

       -e <num>
              Percentage of the pages in the cache that should be clean (default: 60%)

       -D <num>
              Perform deadlock detection every <num> milliseconds (0 to disable, default: 100ms)

       -N     Enable DB_TXN_NOSYNC for a large performance gain (default: off)

       -E     Automatically remove log files that are no longer needed

       -X     Allocate region memory from the heap (default: off)

   Replication Options
       -R     Identifies the host and port used by this site (required)

       -O     Identifies another site participating in this replication group

       -M/-S  Start memcachedb as a master or slave

       -n <num>
              Number of sites participating in replication (default: 2)

CAVEATS

       •   Because  this  is  a  persistent  storage  solution,  expire  time  specified  in  the
           corresponding memcache protocol clients will be silently discarded.

FILES

       /etc/memcachedb.conf

SEE ALSO

       memcached(1)

AUTHOR

       MemcacheDB was written and  is  maintained  by  Steve  Chu  <stvchu@gmail.com>,  based  on
       Memcached by Danga Interactive, Inc. <http://www.danga.com/>

                                          05 February 11                            MEMCACHEDB(1)