Install Memcached PHP Extension in CentOS

Memcached is a general-purpose distributed memory caching system that was originally developed by Danga Interactive for LiveJournal, but is now used by many other sites. It is often used to speed up dynamic database-driven websites by caching data and objects in RAM to reduce the number of times an external data source (such as a database or API) must be read. Memcached runs on Unix, Linux, Windows and Mac OS X and is distributed under a permissive free software license.

Memcached’s APIs provide a giant hash table distributed across multiple machines. When the table is full, subsequent inserts cause older data to be purged in least recently used (LRU) order. Applications using Memcached typically layer requests and additions into RAM before falling back on a slower backing store, such as a database.

The system is used by sites including YouTube, Reddit, Zynga, Facebook, Orange, Twitter and Wikipedia. Engine Yard is using Memcached as the part of their platform as a service technology stack and Heroku offers a managed Memcached service built on Couchbase Server as part of their platform as a service. Google App Engine, AppScale, Windows Azure and Amazon Web Services also offer a Memcached service through an API.


Install Memcached daemon:

The Memcached software doesn’t exist in the standard CentOS repository. You can download from EPEL repository.

Update the repositories:

yum update -y

Start the installation:

yum install memcached

Configure Memcached:

vi   /etc/sysconfig/memcached

Start Memcached:

chkconfig --levels 235 memcached on
/etc/init.d/memcached start

Check and verify Memcached

root@ns5001089 [~]# netstat -an | grep 11211
tcp 0 0* LISTEN
tcp 0 0 TIME_WAIT
tcp 0 0 :::11211 :::* LISTEN
udp 0 0*
udp 0 0 :::11211 :::*
root@ns5001089 [~]# memcached-tool localhost:11211 stats
#localhost:11211 Field Value
accepting_conns 1
auth_cmds 0
auth_errors 0
bytes 44808145
bytes_read 45373990
bytes_written 71278002
cas_badval 0
cas_hits 0
cas_misses 0
cmd_flush 0
cmd_get 4073
cmd_set 546
conn_yields 0
connection_structures 16
curr_connections 10
curr_items 531
decr_hits 0
decr_misses 0
delete_hits 0
delete_misses 0
evictions 0
get_hits 744
get_misses 3329
incr_hits 0
incr_misses 0
limit_maxbytes 2147483648
listen_disabled_num 0
pid 14356
pointer_size 64
rusage_system 2.628164
rusage_user 2.664166
threads 4
time 1366212222
total_connections 3004
total_items 546
uptime 237459
version 1.4.4
root@ns5001089 [~]#


Memcached PHP Extension

Install Pecl too:

yum install php-pear
yum install php-pecl-memcache

Then Start using pecl to fetch PHP Extensions:

pecl install memcache
downloading memcache-2.2.7.tgz ...
Starting to download memcache-2.2.7.tgz (36,459 bytes)
..........done: 36,459 bytes
11 source files, building
running: phpize
Configuring for:
PHP Api Version: 20090626
Zend Module Api No: 20090626
Zend Extension Api No: 220090626
Enable memcache session handler support? [yes] :
building in /root/tmp/pear/pear-build-rootkFeKkf/memcache-2.2.7
running: /root/tmp/pear/memcache/configure --enable-memcache-session=yes
checking for grep that handles long lines and -e... /bin/grep
checking for egrep... /bin/grep -E
checking for a sed that does not truncate output... /bin/sed
checking for cc... cc
checking for C compiler default output file name... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables...
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether cc accepts -g... yes
checking for cc option to accept ISO C89... none needed
checking how to run the C preprocessor... cc -E
checking for icc... no
checking for suncc... no
checking whether cc understands -c and -o together... yes
checking for system library directory... lib
checking if compiler supports -R... no
checking if compiler supports -Wl,-rpath,... yes
checking build system type... x86_64-unknown-linux-gnu
checking host system type... x86_64-unknown-linux-gnu
checking target system type... x86_64-unknown-linux-gnu
checking for PHP prefix... /usr/local
checking for PHP includes... -I/usr/local/include/php -I/usr/local/include/php/main -I/usr/local/include/php/TSRM -I/usr/local/include/php/Zend -I/usr/local/include/php/ext -I/usr/local/include/php/ext/date/lib
checking for PHP extension directory... /usr/local/lib/php/extensions/no-debug-non-zts-20090626
checking for PHP installed headers prefix... /usr/local/include/php
checking if debug is enabled... no
checking if zts is enabled... no
checking for re2c... re2c
checking for re2c version... 0.13.5 (ok)
checking for gawk... gawk
checking whether to enable memcache support... yes, shared
checking whether to enable memcache session handler support... yes
checking for the location of ZLIB... no
checking for the location of zlib... /usr
checking for session includes... /usr/local/include/php
checking for memcache session support... enabled
checking for ld used by cc... /usr/bin/ld
checking if the linker (/usr/bin/ld) is GNU ld... yes
checking for /usr/bin/ld option to reload object files... -r
checking for BSD-compatible nm... /usr/bin/nm -B
checking whether ln -s works... yes
checking how to recognize dependent libraries... pass_all
checking for ANSI C header files... yes
checking for sys/types.h... yes
checking for sys/stat.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for memory.h... yes
checking for strings.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for unistd.h... yes
checking dlfcn.h usability... yes
checking dlfcn.h presence... yes
checking for dlfcn.h... yes
checking the maximum length of command line arguments... 1572864
checking command to parse /usr/bin/nm -B output from cc object... ok
checking for objdir... .libs
checking for ar... ar
checking for ranlib... ranlib
checking for strip... strip
checking if cc supports -fno-rtti -fno-exceptions... no
checking for cc option to produce PIC... -fPIC
checking if cc PIC flag -fPIC works... yes
checking if cc static flag -static works... yes
checking if cc supports -c -o file.o... yes
checking whether the cc linker (/usr/bin/ld -m elf_x86_64) supports shared libraries... yes
checking whether -lc should be explicitly linked in... no
checking dynamic linker characteristics... GNU/Linux
checking how to hardcode library paths into programs... immediate
checking whether stripping libraries is possible... yes
checking if libtool supports shared libraries... yes
checking whether to build shared libraries... yes
checking whether to build static libraries... no
creating libtool
appending configuration tag "CXX" to libtool
configure: creating ./config.status
config.status: creating config.h
running: make
cc -shared .libs/memcache.o .libs/memcache_queue.o .libs/memcache_standard_hash.o .libs/memcache_consistent_hash.o .libs/memcache_session.o -Wl,-soname -Wl, -o .libs/
(cd .libs && rm -f && ln -s ../
/bin/sh /root/tmp/pear/pear-build-rootkFeKkf/memcache-2.2.7/libtool --mode=install cp ./ /root/tmp/pear/pear-build-rootkFeKkf/memcache-2.2.7/modules
cp ./.libs/ /root/tmp/pear/pear-build-rootkFeKkf/memcache-2.2.7/modules/
cp ./.libs/memcache.lai /root/tmp/pear/pear-build-rootkFeKkf/memcache-2.2.7/modules/
PATH="$PATH:/sbin" ldconfig -n /root/tmp/pear/pear-build-rootkFeKkf/memcache-2.2.7/modules
Libraries have been installed in:
If you ever happen to want to link against installed libraries
in a given directory, LIBDIR, you must either use libtool, and
specify the full pathname of the library, or use the `-LLIBDIR'
flag during linking and do at least one of the following:
- add LIBDIR to the `LD_LIBRARY_PATH' environment variable
during execution
- add LIBDIR to the `LD_RUN_PATH' environment variable
during linking
- use the `-Wl,--rpath -Wl,LIBDIR' linker flag
- have your system administrator add LIBDIR to `/etc/'
See any operating system documentation about shared libraries for
more information, such as the ld(1) and manual pages.
Build complete.
Don't forget to run 'make test'.
running: make INSTALL_ROOT="/root/tmp/pear/pear-build-rootkFeKkf/install-memcache-2.2.7" install
Installing shared extensions: /root/tmp/pear/pear-build-rootkFeKkf/install-memcache-2.2.7/usr/local/lib/php/extensions/no-debug-non-zts-20090626/
running: find "/root/tmp/pear/pear-build-rootkFeKkf/install-memcache-2.2.7" | xargs ls -dils
1199741 4 drwxr-xr-x 3 root root 4096 Apr 17 10:32 /root/tmp/pear/pear-build-rootkFeKkf/install-memcache-2.2.7
1199770 4 drwxr-xr-x 3 root root 4096 Apr 17 10:32 /root/tmp/pear/pear-build-rootkFeKkf/install-memcache-2.2.7/usr
1199771 4 drwxr-xr-x 3 root root 4096 Apr 17 10:32 /root/tmp/pear/pear-build-rootkFeKkf/install-memcache-2.2.7/usr/local
1199772 4 drwxr-xr-x 3 root root 4096 Apr 17 10:32 /root/tmp/pear/pear-build-rootkFeKkf/install-memcache-2.2.7/usr/local/lib
1199773 4 drwxr-xr-x 3 root root 4096 Apr 17 10:32 /root/tmp/pear/pear-build-rootkFeKkf/install-memcache-2.2.7/usr/local/lib/php
1199774 4 drwxr-xr-x 3 root root 4096 Apr 17 10:32 /root/tmp/pear/pear-build-rootkFeKkf/install-memcache-2.2.7/usr/local/lib/php/extensions
1199775 4 drwxr-xr-x 2 root root 4096 Apr 17 10:32 /root/tmp/pear/pear-build-rootkFeKkf/install-memcache-2.2.7/usr/local/lib/php/extensions/no-debug-non-zts-20090626
1199769 248 -rwxr-xr-x 1 root root 246440 Apr 17 10:32 /root/tmp/pear/pear-build-rootkFeKkf/install-memcache-2.2.7/usr/local/lib/php/extensions/no-debug-non-zts-20090626/
Build process completed successfully
Installing '/usr/local/lib/php/extensions/no-debug-non-zts-20090626/'
install ok: channel://
Extension memcache enabled in php.ini

Restart Apache:

/etc/init.d/httpd   restart

Check Memcached plugin in PHP:

php -i | grep memcach
memcache support => enabled
memcache.allow_failover => 1 => 1
memcache.chunk_size => 8192 => 8192
memcache.default_port => 11211 => 11211
memcache.default_timeout_ms => 1000 => 1000
memcache.hash_function => crc32 => crc32
memcache.hash_strategy => standard => standard
memcache.max_failover_attempts => 20 => 20
Registered save handlers => files user sqlite memcache