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Fix unix sockets support under FreeBSD.
author Maxim Dounin <>
date Wed, 03 Oct 2007 05:34:42 +0400
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.TH MEMCACHED 1 "April 11, 2005"
memcached \- high-performance memory object caching system
.B memcached
.RI [ options ]
This manual page documents briefly the
.B memcached
memory object caching daemon.
.B 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.
These programs follow the usual GNU command line syntax. A summary of options 
is included below.
.B \-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 interface is suggested.
.B \-d
Run memcached as a daemon.
.B \-u <username> 
Assume the identity of <username> (only when run as root).
.B \-m <num>
Use <num> MB memory max to use for object storage; the default is 64 megabytes.
.B \-c <num>
Use <num> max simultaneous connections; the default is 1024.
.B \-k 
Lock down all paged memory. This is a somewhat dangerous option with large
caches, so consult the README and memcached homepage for configuration
.B \-p <num> 
Listen on TCP port <num>, the default is port 11211.
.B \-U <num> 
Listen on UDP port <num>, the default is port 11211.
.B \-M
Disable automatic removal of items from the cache when out of memory.
Additions will not be possible until adequate space is freed up.
.B \-r
Raise the core file size limit to the maximum allowable.
.B \-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.
.B \-s <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.
.B \-h
Show the version of memcached and a summary of options.
.B \-v
Be verbose during the event loop; print out errors and warnings.
.B \-vv
Be even more verbose; same as \-v but also print client commands and 
.B \-i
Print memcached and libevent licenses.
.B \-P <filename>
Print pidfile to <filename>, only used under -d option.
.B \-t <threads>
Number of threads to use to process incoming requests. This option is only
meaningful if memcached 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.
.B \-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.
The memcached daemon is copyright Danga Interactive and is distributed under 
the BSD license. Note that daemon clients are licensed separately.
The README file that comes with memcached
The memcached daemon was written by Anatoly Vorobey 
.B <>
and Brad Fitzpatrick 
.B <> 
and the rest of the crew of Danga Interactive