#Memcached系列#（2）在Windows环境下安装Memcached

本篇文章主要是讲如何在Windows操作系统上安装Memcached。
原文地址：Installing Memcached on Windows

在上一篇文章当中，主要先简述了一下Object Caching存在的缺点，接着又说明了一下Memcached可以避免这些缺点，最后，说Memcached的分为两部分：Memcached Server和Memcached Client两部分。本文，就是讲述Memcached Server如何安装。

值得注意的是，Memcached的windows binary主要有两个主要来源：Jellycan和Northscale。之所以强调这个问题，是因为今天上午和下午一直没有安装成功，到后来才发现有这个差异，发现这个差异之后，才安装成功了。

【Memcached的简介】Memcached is a high performance, in-memory key-value store or caching system. Its main purpose is to speed up web applications by caching database queries, contents, or other computed results.

【Memcached的由来】Memcached is originally a linux application, but since it is open-source, it has been compiled for windows. 【Memcached的两个主要来源】There are two major sources for the pre-built windows binary: Jellycan and Northscale, and both versions can be used. The following are the download links for the memcached windows binaries:

http://code.jellycan.com/files/memcached-1.2.5-win32-bin.zip
http://code.jellycan.com/files/memcached-1.2.6-win32-bin.zip
http://downloads.northscale.com/memcached-win32-1.4.4-14.zip
http://downloads.northscale.com/memcached-win64-1.4.4-14.zip
http://downloads.northscale.com/memcached-1.4.5-x86.zip
http://downloads.northscale.com/memcached-1.4.5-amd64.zip

在本文的结尾处，有这6个版本的打包附件，还有一个地址：http://blog.elijaa.org/2010/10/15/memcached-for-windows/

【在1.4.5之前的版本，可以将Memcached安装为Windows的服务】In versions earlier than 1.4.5, memcached can install itself as a service. 【在1.4.5之后，Memcached就不能再安装为Windows服务了】However, the ability to run memcached as a service is removed since version 1.4.5. 【因此，安装步骤也分为两部分】Therefore, the installation steps are divided into two categories, part A for memcached prior to version 1.4.5. and part B for memcached version 1.4.5 and later.

A) Installation of memcached < 1.4.5:

Extract the memcached windows binary to any directroy.

In versions earlier than 1.4.5, memcached can install itself as a service. Run a command prompt with elevated privileges, and type:

c:\memcached\memcached.exe -d install

* Replace c:\memcached\memcached.exe with the actual path of your installation.

Then, start or stop the memcached service with the following command:

c:\memcached\memcached.exe -d start
c:\memcached\memcached.exe -d stop

To change the configuration of memcached, run regedit.exe and navigate to the key "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\memcached". Suppose you wish to increase the memory limit of memcached, edit the value of ImagePath to the following:

"c:\memcached\memcached.exe" -d runservice -m 512

* Besides '-m 512', you may also append other memcached parameters to the path. Run "c:\memcached\memcached.exe -h" to view the list of available parameters.

Meanwhile, to uninstall the memcached serivce, run the following command:

c:\memcached\memcached.exe -d uninstall

B) Installation of memcached >= 1.4.5:

Extract the memcached windows binary to any directroy.

In version 1.4.5 or later, memcached cannot run as a service. It must be started as a normal process using the task scheduler. To configure the memcached process to run automatically every time windows start, run a command prompt and type the following:

schtasks /create /sc onstart /tn memcached /tr "'c:\memcached\memcached.exe' -m 512"

* Replace c:\memcached\memcached.exe with the actual path of your installation.
** Besides '-m 512', you may also append other memcached parameters to the path. Run "c:\memcached\memcached.exe -h" to view the list of available parameters.

Meanwhile, to remove the scheduled memcached task, run the following command:

schtasks /delete /tn memcached

补充一下常用设置
常用设置：
-p <num> 监听的端口
-l <ip_addr> 连接的IP地址, 默认是本机
-d start 启动memcached服务
-d restart 重起memcached服务
-d stop|shutdown 关闭正在运行的memcached服务
-d install 安装memcached服务
-d uninstall 卸载memcached服务
-u <username> 以<username>的身份运行 (仅在以root运行的时候有效)
-m <num> 最大内存使用，单位MB。默认64MB
-M 内存耗尽时返回错误，而不是删除项
-c <num> 最大同时连接数，默认是1024
-f <factor> 块大小增长因子，默认是1.25
-n <bytes> 最小分配空间，key+value+flags默认是48
-h 显示帮助

Memcached statistics

To view the statistics for memcached, bring up a telnet connection to memcached by the command:

telnet 127.0.0.1 11211

Then, type stats and enter.
Here is an explanation of the different memcached stats.

Name	Type	Meaning
Name	Type	Meaning
pid	32u	Process id of this server process
uptime	32u	Number of secs since the server started
time	32u	current UNIX time according to the server
version	string	Version string of this server
pointer_size	32	Default size of pointers on the host OS (generally 32 or 64)
rusage_user	32u.32u	Accumulated user time for this process (seconds:microseconds)
rusage_system	32u.32u	Accumulated system time for this process (seconds:microseconds)
curr_items	32u	Current number of items stored
total_items	32u	Total number of items stored since the server started
bytes	64u	Current number of bytes used to store items
curr_connections	32u	Number of open connections
total_connections	32u	Total number of connections opened since the server started running
connection_structures	32u	Number of connection structures allocated by the server
reserved_fds	32u	Number of misc fds used internally
cmd_get	64u	Cumulative number of retrieval reqs
cmd_set	64u	Cumulative number of storage reqs
cmd_flush	64u	Cumulative number of flush reqs
cmd_touch	64u	Cumulative number of touch reqs
get_hits	64u	Number of keys that have been requested and found present
get_misses	64u	Number of items that have been requested and not found
delete_misses	64u	Number of deletions reqs for missing keys
delete_hits	64u	Number of deletion reqs resulting in an item being removed.
incr_misses	64u	Number of incr reqs against missing keys.
incr_hits	64u	Number of successful incr reqs.
decr_misses	64u	Number of decr reqs against missing keys.
decr_hits	64u	Number of successful decr reqs.
cas_misses	64u	Number of CAS reqs against missing keys.
cas_hits	64u	Number of successful CAS reqs.
cas_badval	64u	Number of CAS reqs for which a key was found, but the CAS value did not match.
touch_hits	64u	Numer of keys that have been touched with a new expiration time
touch_misses	64u	Numer of items that have been touched and not found
auth_cmds	64u	Number of authentication commands handled, success or failure.
auth_errors	64u	Number of failed authentications.
evictions	64u	Number of valid items removed from cache to free memory for new items
reclaimed	64u	Number of times an entry was stored using memory from an expired entry
bytes_read	64u	Total number of bytes read by this server from network
bytes_written	64u	Total number of bytes sent by this server to network
limit_maxbytes	32u	Number of bytes this server is allowed to use for storage.
threads	32u	Number of worker threads requested. (see doc/threads.txt)
conn_yields	64u	Number of times any connection yielded to another due to hitting the -R limit.
hash_power_level	32u	Current size multiplier for hash table
hash_bytes	64u	Bytes currently used by hash tables
hash_is_expanding	bool	Indicates if the hash table is being grown to a new size
expired_unfetched	64u	Items pulled from LRU that were never touched by get/incr/append/etc before expiring
evicted_unfetched	64u	Items evicted from LRU that were never touched by get/incr/append/etc.
slab_reassign_running	bool	If a slab page is being moved
slabs_moved	64u	Total slab pages moved
crawler_reclaimed	64u	Total items freed by LRU Crawler
lrutail_reflocked	64u	Times LRU tail was found with active ref. Items moved to head to avoid OOM errors.

Source: https://github.com/memcached/memcached/blob/master/doc/protocol.txt

还有一个地方可以下载：http://blog.elijaa.org/2010/10/15/memcached-for-windows/

This post contains various binaries versions of Memcached for Windows as finding some of them may be difficult.

Memcached 1.2.X

Memcached 1.2.4 for Windows (32 Bits) : memcached 1.2.4 win32.zip
Memcached 1.2.5 for Windows (32 Bits) : memcached 1.2.5 win32.zip
Memcached 1.2.6 for Windows (32 Bits) : memcached 1.2.6 win32.zip

Memcached 1.4.X

Memcached 1.4.2 for Windows (32 Bits) : memcached 1.4.2 win32.zip
Memcached 1.4.4 for Windows (32 Bits) : memcached 1.4.4 win32.rar
Memcached 1.4.5 for Windows (32 Bits) : memcached 1.4.5 win32.zip
Memcached 1.4.5 for Windows (64 Bits) : memcached 1.4.5 win64.zip

Credits

All credits goes to Jellycan for 1.2.5 and 1.2.6 and Northscale (now Membase) for 1.4.X.