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