Is it normal to have a 16 percent virtual memory overhead in memcached on x86_64 linux? memcached STAT bytes is reporting 3219 megabytes of data, but virtual memory is 16 percent higher at 3834. Resident memory is 14 percent higher at 3763 megabytes.
Is there a way to tune linux/memcached to get memcached to consume less virtual memory? At the moment, my 4GB system is full with 3219 megabtyes of data loaded in memcached. I am seeing lots of evictions when I try to load more data. Below is my configuration and stats. Ubuntu SMP x86_64 2.6.35-22-server memcached version 1.4.5-1ubuntu1 libevent-1.4-2 version 1.4.13-stable-1 I am using the default settings for memcached, namely, chunk_size of 48 and 4 threads. Stack size on my linux system is set to 8192 kilobytes. Should I reduce the stack size? I am using the default slab page size of 1MB. Should I reduce this amount? system: using free 3954 megabytes total memory 3928 megabytes used 26 megabytes free memcached process: using ps 3763 megabytes RSS 3834 megabytes VSZ 3219 megabtyes reported by STAT bytes settings: STAT maxbytes 3879731200 STAT maxconns 1024 STAT tcpport 11211 STAT udpport 11211 STAT inter NULL STAT verbosity 0 STAT oldest 0 STAT evictions on STAT domain_socket NULL STAT umask 700 STAT growth_factor 1.25 STAT chunk_size 48 STAT num_threads 4 STAT stat_key_prefix : STAT detail_enabled no STAT reqs_per_event 20 STAT cas_enabled yes STAT tcp_backlog 1024 STAT binding_protocol auto-negotiate STAT auth_enabled_sasl no STAT item_size_max 1048576 STAT pid 716 STAT uptime 10271 STAT time 1311199316 STAT version 1.4.5 STAT pointer_size 64 STAT rusage_user 175.140000 STAT rusage_system 325.200000 STAT curr_connections 11 STAT total_connections 73 STAT connection_structures 30 STAT cmd_get 9137902 STAT cmd_set 9067050 STAT cmd_flush 0 STAT get_hits 337524 STAT get_misses 8800378 STAT delete_misses 0 STAT delete_hits 266674 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 auth_cmds 0 STAT auth_errors 0 STAT bytes_read 3468460589 STAT bytes_written 244250132 STAT limit_maxbytes 3879731200 STAT accepting_conns 1 STAT listen_disabled_num 0 STAT threads 4 STAT conn_yields 0 STAT bytes 3376314121 STAT curr_items 8080800 STAT total_items 9067050 STAT evictions 719576 STAT reclaimed 0
