this tutorial tested on debian 8 and working as well
**1 Requirements **
Debian 8 with Apache web server installed.
Root access to the server
2 Installing mod_pagespeed
Debian 64 bit
cd /tmp
wget https://dl-ssl.google.com/dl/linux/direct/mod-pagespeed-stable_current_amd64.deb
dpkg -i mod-pagespeed-stable_current_amd64.deb
Debian 32 bit
cd /tmp
wget https://dl-ssl.google.com/dl/linux/direct/mod-pagespeed-stable_current_i386.deb
dpkg -i mod-pagespeed-stable_current_i386.deb
**restart apache **
service apache2 restart
3 Installing Memcached
apt-get install memcached
And check with the command "netstat -tap | grep memcached" if memcached is running
netstat -tap | grep memcached
The result:
root@localhost:/tmp# netstat -tap | grep memcached
tcp 0 0 localhost:11211 *:* LISTEN 35396/memcached
In the output, we see the port were Memcached is listening on: 11211, we need that port for the next step.
Configure mod_pagespeed to use memcached
nano /etc/apache2/mods-available/pagespeed.conf
find the line
[....]
# ModPagespeedMemcachedServers localhost:11211
[....]
and remove the #, so that it looks like this:
[....]
ModPagespeedMemcachedServers localhost:11211
[....]
If you have plenty of memory in your server, then you can get a further speedup by removing the # in front of this line:
[....]
ModPagespeedCreateSharedMemoryMetadataCache "/var/cache/mod_pagespeed/" 51200
[....]
restart apache
service apache2 restart
Now mod_pagespeed will use memcached as storage backend. You can get usage statistics from memcached with the following command:
echo stats | nc 127.0.0.1 11211
root@localhost:/tmp# echo stats | nc 127.0.0.1 11211
STAT pid 35396
STAT uptime 72
STAT time 1458293309
STAT version 1.4.21
STAT libevent 2.0.21-stable
STAT pointer_size 64
STAT rusage_user 0.008000
STAT rusage_system 0.000000
STAT curr_connections 5
STAT total_connections 6
STAT reserved_fds 20
STAT cmd_get 0
STAT cmd_set 0
STAT cmd_flush 0
STAT cmd_touch 0
STAT get_hits 0
STAT get_misses 0
STAT delete_misses 0
STAT delete_hits 0
STAT incr_misses 0
STAT incr_hits 0
STAT decr_misses 0
STAT decr_hits 0
STAT cas_misses 0
STAT cas_hits 0
STAT cas_badval 0
STAT touch_hits 0
STAT touch_misses 0
STAT auth_cmds 0
STAT auth_errors 0
STAT bytes_read 6
STAT bytes_written 0
STAT limit_maxbytes 67108864
STAT accepting_conns 1
STAT listen_disabled_num 0
STAT threads 4
STAT conn_yields 0
STAT hash_power_level 16
STAT hash_bytes 524288
STAT hash_is_expanding 0
STAT malloc_fails 0
STAT bytes 0
STAT curr_items 0
STAT total_items 0
STAT expired_unfetched 0
STAT evicted_unfetched 0
STAT evictions 0
STAT reclaimed 0
STAT crawler_reclaimed 0
STAT lrutail_reflocked 0
END
Press [ctrl] + c to get back to the command prompt.
best regards