MEMCACHEDB(1) General Commands Manual MEMCACHEDB(1)
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
o 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)