printf "stats\r\n" | nc 127.0.0.1 11211 

STAT pid 2529 
STAT uptime 1078133 
STAT time 1241415864 
STAT version 1.2.4 
STAT pointer_size 64 
STAT rusage_user 489.302614 
STAT rusage_system 6850.564555 
STAT curr_items 2537 
STAT total_items 872539 
STAT bytes 9939637 
STAT curr_connections 17 
STAT total_connections 6166911 
STAT connection_structures 110 
STAT cmd_get 68414905 
STAT cmd_set 872539 
STAT get_hits 67605437 
STAT get_misses 809468 
STAT evictions 0 
STAT bytes_read 921056148171 
STAT bytes_written 2323979209207 
STAT limit_maxbytes 134217728 
STAT threads 4 
END 

一、缓存命中率 = get_hits/cmd_get * 100%

二、get_misses的数字加上get_hits应该等于cmd_get

三、total_items == cmd_set == get_misses，当可用最大内存用光时，memcached就会删掉一些内容，等式就会不成立