The document describes how to configure and use memcached. It shows how to install memcached, set runtime options like memory size and number of connections, and check the status and settings using the telnet client. It also provides examples of integrating memcached monitoring into Nagios/Icinga using checks for connections and specific keys.

24. my $memd = Cache::Memcached::Fast->new({
servers => [qw!192.168.67.31:11211 192.168.67.32:11211!]
});
if ( my $nickname = $memd->get('nickname:1') ) {
return $nickname;
}
my $dbh = DBI->connect('DBI:mysql:boofy:host=localhost');
my $nickname = $dbh->selectrow_array(
'SELECT nickname FROM user WHERE id=?', undef, 1);
if ( $nickname ) {
$memd->add('nickname:1', $nickname, 24*60*60);
return $nickname;
}
return;

25. % ./memstrike -l localhost -p 11211 -t 10 -k 8 -v 8 50000
number of threads : 10
number of requests : 50000
requests per thread : 5000
get multiplex : 1
size of key : 8 bytes
size of value : 8 bytes
----
[gggggggggg] ...
0.683260 sec
0.762939 MB
9.366859 Mbps
73178.585019 req/sec
13.665200 usec/req

27. VS

28. VS

31. memcached ×

36. % sudo ./memcached -c 262144 -u nobody

37. 4532 int maxfiles = settings.maxconns;
4533 if (rlim.rlim_cur < maxfiles)
4534 rlim.rlim_cur = maxfiles;
4535 if (rlim.rlim_max < rlim.rlim_cur)
4536 rlim.rlim_max = rlim.rlim_cur;
4537 if (setrlimit(RLIMIT_NOFILE, &rlim) != 0) {
4538 fprintf(stderr, "failed to set rlimit for open
files. Try running as root or requesting smaller
maxconns value.n");
4539 exit(EX_OSERR);
4540 }

39. % ./memcached -l 127.0.0.1
% ./memcached -l 192.168.67.31

40. % ./memcached -l 192.168.67.31
..
% ssh myserver
% telnet localhost 11211
Trying ::1...
Trying 127.0.0.1...
telnet: Unable to connect to remote host:
Connection refused

41. % sudo ./memcached -c 262144 -u nobody

43. % ./memcached -vvv
slab class 1: chunk size 96 perslab 10922
slab class 40: chunk size 1048576 perslab 1
<26 server listening (auto-negotiate)
<27 server listening (auto-negotiate)
<28 send buffer was 124928, now 268435456
<28 server listening (udp)
<28 server listening (udp)
<28 server listening (udp)
<28 server listening (udp)
<29 send buffer was 124928, now 268435456
<29 server listening (udp)
<29 server listening (udp)
<29 server listening (udp)
<29 server listening (udp)

44. % ./memcached -p 11211 -U 0

45. % ./memcached -U 0
% ./memcached -U 12345

46. % ./memcached -m 16G

47. % ./memcached -C -m 16G

48. % ./memcached -c 32768 -u nobody
-C -m 16G -p 11211 -U 0

49. % telnet localhost 11211
Trying ::1...
Connected to localhost.
Escape character is '^]'.
stats settings
STAT maxbytes 16777216
STAT maxconns 32768
STAT tcpport 11211
STAT udpport 0
STAT inter NULL
STAT verbosity 0
STAT oldest 0
STAT evictions on
STAT growth_factor 1.25
STAT chunk_size 48
STAT num_threads 4
STAT cas_enabled no
STAT tcp_backlog 4096
STAT binding_protocol auto-negotiate
STAT auth_enabled_sasl no
STAT item_size_max 1048576
END

58. define host{
use generic-host
host_name memserver
alias memserver
address 192.168.67.30
}
define service{
use generic-service
host_name memserver
service_description memcached
check_command check_memcached
}
define command {
command_name check_memcached
command_line ...
}

59. define command {
command_name check_memcached
command_line $USER1$/check_tcp
-H $HOSTADDRESS$
-p 11211
-t 5
}

60. define command {
command_name check_memcached
command_line $USER1$/check_tcp
-H $HOSTADDRESS$
-p 11211
-t 5
-s 'statsrnquitrn'
-E
-e 'uptime'
-M crit
}

61. stats STAT decr_misses 0
STAT pid 4825 STAT decr_hits 0
STAT uptime 7842604 STAT cas_misses 0
STAT time 1284432055 STAT cas_hits 0
STAT version 1.4.4 STAT cas_badval 0
STAT pointer_size 32 STAT auth_cmds 0
STAT rusage_user 23623.394698 STAT auth_errors 0
STAT rusage_system 31550.652571 STAT bytes_read 219935315170
STAT curr_connections 1243 STAT bytes_written 788448026716
STAT total_connections 30886226 STAT limit_maxbytes 1073741824
STAT connection_structures 1373 STAT accepting_conns 1
STAT cmd_get 730786415 STAT listen_disabled_num 0
STAT cmd_set 345660130 STAT threads 4
STAT cmd_flush 0 STAT conn_yields 146
STAT get_hits 455135951 STAT bytes 740742845
STAT get_misses 275650464 STAT curr_items 3623646
STAT delete_misses 17887026 STAT total_items 347251509
STAT delete_hits 10283848 STAT evictions 6986784
STAT incr_misses 4281893 END
STAT incr_hits 111734935

64. #!/usr/local/bin/activeperl
use strict;
use warnings;
use Getopt::Long;
use IO::Socket::INET;
GetOptions(
'H=s' => my $HOST,
'p=s' => my $PORT,
'k=s' => my $KEY
);
my $sock = IO::Socket::INET->new(
PeerAddr => $HOST, PeerPort => $PORT
);
if ( !$sock ) {
print "Couldnt connect to $HOST:$PORT: $!n";
exit(3);
}
$sock->syswrite("get $KEYrn");
$sock->sysread( my $result, 16 );
if ( $result =~ m!^VALUE! ) {
exit(0); #OK
}
print "Not found $KEY on $HOST:$PORTn";
exit(2);

65. define command {
command_name check_memcached
command_line $USER1$/check_memkey.pl
-H $HOSTADDRESS$
-p 11211
-k dankogai
}

69. $ sudo yum install net-snmp net-snmp-perl
rrdtool rrdtool-perl
$ git clone git://github.com/kazeburo/cloudforecast.git
$ cd cloudforecast
$ curl -L -o cpanm http://cpanmin.us/
$ chmod u+x cpanm
$ ./cpanm -l extlib --installdeps .

70. #
$ cp cloudforecast_sample.yaml cloudforecast.yaml
#
$ cat server_list.yaml
--- #Memcached
servers:
- config: memcached.yaml
hosts:
- 192.168.67.30 memserver memcached server
- 192.168.67.31 memserver memcached server
#
$ cat host_config/memcached.yaml
resources:
- traffic:eth1
- basic
- memcached:11211

71. # Web port 5000 Listen
$ ./cloudforecast_web -p 5000
-c cloudforecast.yaml -l server_list.yaml
# 5
$ ./cloudforecast_radar -c cloudforecast.yaml
-l server_list.yaml

79. STAT 1:chunk_size 80 STAT 2:cmd_set 34606948
STAT 1:chunks_per_page 13107 STAT 2:delete_hits 19083
STAT 1:total_pages 1 STAT 2:incr_hits 283422
STAT 1:total_chunks 13107 STAT 2:decr_hits 0
STAT 1:used_chunks 3 STAT 2:cas_hits 0
STAT 1:free_chunks 32 STAT 2:cas_badval 0
STAT 1:free_chunks_end 13072 ..
STAT 1:mem_requested 220 STAT 42:chunk_size 1048576
STAT 1:get_hits 4438 STAT 42:chunks_per_page 1
STAT 1:cmd_set 11998 STAT 42:total_pages 1
STAT 1:delete_hits 0 STAT 42:total_chunks 1
STAT 1:incr_hits 0 STAT 42:used_chunks 1
STAT 1:decr_hits 0 STAT 42:free_chunks 0
STAT 1:cas_hits 0 STAT 42:free_chunks_end 0
STAT 1:cas_badval 0 STAT 42:mem_requested 779480
STAT 2:chunk_size 104 STAT 42:get_hits 81
STAT 2:chunks_per_page 10082 STAT 42:cmd_set 665
STAT 2:total_pages 16 STAT 42:delete_hits 0
STAT 2:total_chunks 161312 STAT 42:incr_hits 0
STAT 2:used_chunks 116168 STAT 42:decr_hits 0
STAT 2:free_chunks 45144 STAT 42:cas_hits 0
STAT 2:free_chunks_end 0 STAT 42:cas_badval 0
STAT 2:mem_requested 11573385 STAT active_slabs 40
STAT 2:get_hits 29690676 STAT total_malloced 1073454184

80. STAT items:1:number 3 STAT items:3:number 1541997
STAT items:1:age 7841268 STAT items:3:age 6285649
STAT items:1:evicted 0 STAT items:3:evicted 2546432
STAT items:1:evicted_nonzero 0 STAT items:3:evicted_nonzero 0
STAT items:1:evicted_time 0 STAT items:3:evicted_time 1557089
STAT items:1:outofmemory 0 STAT items:3:outofmemory 0
STAT items:1:tailrepairs 0 STAT items:3:tailrepairs 0
STAT items:2:number 116210 ...
STAT items:2:age 6150456 STAT items:42:number 1
STAT items:2:evicted 269 STAT items:42:age 7834430
STAT items:2:evicted_nonzero 0 STAT items:42:evicted 0
STAT items:2:evicted_time 1594950 STAT items:42:evicted_nonzero 0
STAT items:2:outofmemory 0 STAT items:42:evicted_time 0
STAT items:2:tailrepairs 0 STAT items:42:outofmemory 0
STAT items:42:tailrepairs 0