Memcached Memcached - before and after graphs!

Nice.. same this forum here uses Memcached too via Centmin Mod LEMP stack

memcached does wonders especially on vB - how's 10 billion cache hits per month ?

 

Was curious myself and for this very light traffic forum it's all PHP time

 

Probably just the default TCP method for memcached I suspect

FYI, there's various ways in SSH to get memcached server stats too

Code:

echo stats | nc 127.0.0.1 11211

gives

Code:

echo stats | nc 127.0.0.1 11211
STAT pid 22582
STAT uptime 24
STAT time 1424349314
STAT version 1.4.22
STAT libevent 2.0.21-stable
STAT pointer_size 64
STAT rusage_user 0.006666
STAT rusage_system 0.033333
STAT curr_connections 5
STAT total_connections 18
STAT connection_structures 6
STAT reserved_fds 20
STAT cmd_get 100
STAT cmd_set 37
STAT cmd_flush 0
STAT cmd_touch 0
STAT get_hits 64
STAT get_misses 36
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 204124
STAT bytes_written 511405
STAT limit_maxbytes 268435456
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 slab_reassign_running 0
STAT slabs_moved 0
STAT malloc_fails 0
STAT bytes 202454
STAT curr_items 37
STAT total_items 37
STAT expired_unfetched 0
STAT evicted_unfetched 0
STAT evictions 0
STAT reclaimed 0
STAT crawler_reclaimed 0
STAT lrutail_reflocked 0
END

via memcached-tool

the options available

Code:

memcached-tool
Usage: memcached-tool <host[:port] | /path/to/socket> [mode]

       memcached-tool 10.0.0.5:11211 display    # shows slabs
       memcached-tool 10.0.0.5:11211            # same.  (default is display)
       memcached-tool 10.0.0.5:11211 stats      # shows general stats
       memcached-tool 10.0.0.5:11211 settings   # shows settings stats
       memcached-tool 10.0.0.5:11211 sizes      # shows sizes stats
       memcached-tool 10.0.0.5:11211 dump       # dumps keys and values

WARNING! sizes is a development command.
As of 1.4 it is still the only command which will lock your memcached instance for some time.
If you have many millions of stored items, it can become unresponsive for several minutes.
Run this at your own risk. It is roadmapped to either make this feature optional
or at least speed it up.

for example stats

Code:

memcached-tool 127.0.0.1:11211 stats

Code:

memcached-tool 127.0.0.1:11211 stats
#127.0.0.1:11211   Field       Value
         accepting_conns           1
               auth_cmds           0
             auth_errors           0
                   bytes      624900
              bytes_read      701739
           bytes_written     5200282
              cas_badval           0
                cas_hits           0
              cas_misses           0
               cmd_flush           0
                 cmd_get         917
                 cmd_set         124
               cmd_touch           0
             conn_yields           0
   connection_structures           9
       crawler_reclaimed           0
        curr_connections           8
              curr_items          98
               decr_hits           0
             decr_misses           0
             delete_hits           0
           delete_misses           0
       evicted_unfetched           0
               evictions           0
       expired_unfetched           0
                get_hits         827
              get_misses          90
              hash_bytes      524288
       hash_is_expanding           0
        hash_power_level          16
               incr_hits           0
             incr_misses           0
                libevent 2.0.21-stable
          limit_maxbytes   268435456
     listen_disabled_num           0
       lrutail_reflocked           0
            malloc_fails           0
                     pid       22582
            pointer_size          64
               reclaimed           0
            reserved_fds          20
           rusage_system    0.079999
             rusage_user    0.039999
   slab_reassign_running           0
             slabs_moved           0
                 threads           4
                    time  1424349464
       total_connections          53
             total_items         124
              touch_hits           0
            touch_misses           0
                  uptime         174
                 version      1.4.22

settings list

Code:

memcached-tool 127.0.0.1:11211 settings
#127.0.0.1:11211   Field       Value
       auth_enabled_sasl          no
        binding_protocol auto-negotiate
             cas_enabled         yes
              chunk_size          72
          detail_enabled          no
           domain_socket        NULL
               evictions          on
           flush_enabled         yes
           growth_factor        1.25
          hash_algorithm     jenkins
          hashpower_init           0
                   inter   127.0.0.1
           item_size_max     1048576
             lru_crawler          no
       lru_crawler_sleep         100
     lru_crawler_tocrawl           0
                maxbytes   268435456
                maxconns        2048
           maxconns_fast          no
             num_threads           4
     num_threads_per_udp           4
                  oldest           0
          reqs_per_event         200
           slab_automove           1
           slab_reassign         yes
         stat_key_prefix           :
        tail_repair_time           0
             tcp_backlog        2048
                 tcpport       11211
                 udpport       11211
                   umask         700
               verbosity           0

Explanation for memcached-tool at MySQL :: MySQL 5.5 Reference Manual :: 16.6.4.6 Using memcached-tool and details on stats output MySQL :: MySQL 5.5 Reference Manual :: 16.6.4.1 memcached General Statistics

Statistic	Data type	Description Version
pid	32u	Process ID of the memcached instance.
uptime	32u	Uptime (in seconds) for this memcached instance.
time	32u	Current time (as epoch).
version	string	Version string of this instance.
pointer_size	string	Size of pointers for this host specified in bits (32 or 64).
rusage_user	32u:32u	Total user time for this instance (seconds:microseconds).
rusage_system	32u:32u	Total system time for this instance (seconds:microseconds).
curr_items	32u	Current number of items stored by this instance.
total_items	32u	Total number of items stored during the life of this instance.
bytes	64u	Current number of bytes used by this server to store items.
curr_connections	32u	Current 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.
cmd_get	64u	Total number of retrieval requests (get operations).
cmd_set	64u	Total number of storage requests (set operations).
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_hits	64u	Number of keys that have been deleted and found present. 1.3.x
delete_misses	64u	Number of items that have been delete and not found. 1.3.x
incr_hits	64u	Number of keys that have been incremented and found present. 1.3.x
incr_misses	64u	Number of items that have been incremented and not found. 1.3.x
decr_hits	64u	Number of keys that have been decremented and found present. 1.3.x
decr_misses	64u	Number of items that have been decremented and not found. 1.3.x
cas_hits	64u	Number of keys that have been compared and swapped and found present. 1.3.x
cas_misses	64u	Number of items that have been compared and swapped and not found. 1.3.x
cas_badvalue	64u	Number of keys that have been compared and swapped, but the comparison (original) value did not match the supplied value. 1.3.x
evictions	64u	Number of valid items removed from cache to free memory for new items.
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 permitted to use for storage.
threads	32u	Number of worker threads requested.
conn_yields	64u	Number of yields for connections (related to the -R option). 1.4.0

 

Better to monitor memory usage and adjust accordingly

As to multiple memcached servers, you can use memcache PHP extensions consistent hash strategy / session redundancy option (already set in Centmin Mod default memcached server/memcache PHP extension setup) so adding more memcached servers if web app supports. However, there's not as great a performance boost for such as there are more advanced methods which allow multiple memcached servers pooled into one cluster with automatic sharding and failover which I've been playing with for my paid client work which allows you to scale memcached servers to 50,000+ concurrent connections easily to scale memcached server caching

 

Nice to see it's working well.. 201 million hits saved from hitting the database

 

You only need to allocate as much memory as your web app (XF) requires for memcached server caching. Allocating more memory doesn't do anything for performance

 

probably cause @RoldanLT and I have other addons which do caching like XenCache Xen Cache | XenForo Community and bd Cache [bd] Cache | XenForo Community and I have ngx_pagespeed enabled too with memcached offloading Nginx, PHP-FPM & MariaDB MySQL | Centmin Mod Community

my memcached stats for this forum

Code:

Free: 76.3 MBytes (29.8%)    Hits: 5692032 (98.7%)
Used: 179.7 MBytes (70.2%)    Misses: 77613 (1.3%)

Cache Information
Current Items(total)    41214 (355735)

 

yeah would think it would be useful for all