memcached
(1m)
名称
memcached - high performance memory object caching system
用法概要
memcached [-l <ip-addr>] [-d] [-u <username>]
[-m <num>] [-c <num>] [-k] [-L ]
[-p <num>] [-U <num>] [-s <filename>]
[-a <perms>] [-M] [-r] [-b]
[-f <factor>] [-n <size>] [-h] [-v] [-vv] [-i]
[-P <filename>] [-t <threads>] [-D <char>]
描述
Administration Commands memcached(1M)
NAME
memcached - high performance memory object caching system
SYNOPSIS
memcached [-l <ip-addr>] [-d] [-u <username>]
[-m <num>] [-c <num>] [-k] [-L ]
[-p <num>] [-U <num>] [-s <filename>]
[-a <perms>] [-M] [-r] [-b]
[-f <factor>] [-n <size>] [-h] [-v] [-vv] [-i]
[-P <filename>] [-t <threads>] [-D <char>]
DESCRIPTION
memcached is a flexible memory object caching daemon
designed to alleviate database load in dynamic web applica-
tions by storing objects in memory. It is based on libevent
to scale to any size needed, and is specifically optimized
to avoid swapping and always use non-blocking I/O. This man
page documents briefly the memcached memory object caching
daemon.
OPTIONS
The options supported by the memcached command are described
below.
-l <ip-addr> Listen on <ip-addr>; default to INADDR_ANY.
This is an important option to consider as
there is no other way to secure the instal-
lation. Binding to an internal or fire
walled network interface is suggested.
-d Run memcached as a daemon.
-u <username> Assume the identity of <username> only when
run as a super user (root).
-m <num> Use the maximum <num> MB memory for object
storage; the default is 64 MB.
-c <num> Use the specified number of maximum simul-
taneous connections; the default is 1024.
-k Lock down all paged memory.
Use this option with caution with large
caches. For information about the configu-
ration suggestions, see the README and the
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memcached home page.
-L Preallocate memory and use large memory
pages if possible.
This option will preallocate cache memory
for object storage. See description of -m
option for a specification of the size of
the memory. If supported by the platform,
large memory pages will be allocated. This
should reduce number of TLB misses and
increase performance.
-p <num> Listen on the TCP port <num>. The default
port is 11211.
-U <num> Listen on the UDP port <num>. The default
is 0, meaning that the UDP protocol is dis-
abled.
-s <filename> Unix socket path to listen on (disables
listening support for TCP and UDP).
-a <perms> Permissions (in octal format) for Unix
socket created with -s option. Default
value is 0700.
-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 maxi-
mum allowable.
-b Run a managed instance.
-f <factor> Use this option to specify <factor> as the
multiplier for computing the sizes of mem-
ory chunks that items are stored in. A
lower value may result in less wasted mem-
ory depending on the total amount of memory
available and the distribution of item
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sizes. The default value is 1.25.
-n <size> Allocate a minimum of <size> bytes for the
item key, value, and flags. The default
value 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, that
is -f option, 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 option but
also print client commands and responses.
-i Display memcached and libevent licenses.
-P <filename> Print pidfile to the specified file.
Note -
This option can be used only when
mechached is run as a daemon (-d option).
-t <threads> Number of threads to use to process incom-
ing requests. The default is 4. It is typ-
ically not useful to set this much higher
than the number of CPU cores on the mem-
cached server.
-D <char> Use the <char> as the delimiter between key
prefixes and IDs. This is used for per-pre-
fix statistics reporting. The default is :
(colon). If this option is specified, sta-
tistics collection is turned on automati-
cally; if not, then it can be turned on by
sending the stats detail on command to the
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server.
EXIT STATUS
The following exit values are returned:
0 command executed successfully
1 error in executing the command
SERVICE MANAGEMENT FACILITY
memcached package for Solaris (service/memcached) includes
files necessary to register with the Service Management
Facility described in SMF(5). The following procedure
describes the steps to automate the service management using
memcached.
1. Add other parameters to be passed to the memcached
service instance.
example: specify the server to use 1024 MB of mem-
ory
example% svccfg
svc:> select memcached
svc:/application/database/memcached> setprop memcached/options=("-m" "1024")
svc:/application/database/memcached> quit
example% svcadm refresh memcached
Note -
The arguments cannot be passed as a single string
because of a limitation in svccfg.
2. Enable memcached .
example% svcadm enable memcached
The state of the service instance changes to
online, and the memcached service instance must be
started:
example% svcs memcached
STATE STIME FMRI
online 1:19:15 svc:/application/database/memcached:default
3. To disable shutdown and automatic restart of
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memcached service instance,
example% svcadm disable memcached
USER AUTHORIZATIONS
You can use RBAC(5) to authorize otherwise non-privileged
users to manage memcached services. To let a user named
myuser change memcached value properties and manage mem-
cached service states, add the following line to
/etc/user_attr:
myuser::::type=role;profiles=Memcached Administration,All
PACKAGE CONTENTS
The memcached package consists of the memcached server and
man pages for the server.
Client libraries can be made available by installing other
packages.
The memcached server is based on the memcached open-source
software available from http://www.danga.com/memcached/.
SECURITY
When the memcached server is started, it listens for network
requests on a TCP port and/or a UDP port. It is important
for the security of the network that you protect this port,
for example, by blocking access to this port in a firewall.
The default TCP port number to use is 11211.
You may use the -p option to set another TCP port number.
There is no default UDP port number. You can use the -U
option to set a UDP port number.
If you are running memcached on a server with multiple net-
work interfaces, you can restrict vulnerability by binding
memcached to a single interface by using the -l option.
Caution -
Note that memcached was designed for speed and not for
security. There is no authentication of requests that go
in to the memcached servers, and communication is not
encrypted. The network that your memcached servers and
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clients run within should be safe-guarded against network
attacks.
ATTRIBUTES
See attributes(5) for descriptions of the following
attributes:
+---------------+-------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+-------------------+
|Availability | service/memcached |
+---------------+-------------------+
|Stability | Uncommitted |
+---------------+-------------------+
SEE ALSO
libmemcached(3libmemcached)
Additional documentation (FAQ) can be found at
http://www.eu.socialtext.net/memcached/index.cgi.
NOTES
LICENSE
The memcached daemon is copyright Danga Interactive and is
distributed under the BSD license. memcached clients are
licensed separately.
This software was built from source available at
https://java.net/projects/solaris-userland. The original
community source was downloaded from http://mem-
cached.org/files/memcached-1.4.17.tar.gz
Further information about this software can be found on the
open source community website at http://memcached.org/.
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