由于运行 Magento 时内存不足，我遇到了 ubuntu 杀死 mySQL 服务器的问题。我已经运行了mySQLtuner 脚本（它警告可能为 mySQL 分配的内存高于系统内存）并相应地调整了 mySQL /etc/mysql/my.cnf 文件。
根据脚本，mySQL 允许的最大内存使用量为 218.9 MB，这不会造成问题。服务器刚启动且一切正常时的可用内存为 277 / 590 MB。在 Magento 前端点击了一段时间后，mySQL 服务器被杀死，这里是 /var/log/syslog 的转储：
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037361] mysqld invoked oom-killer: gfp_mask=0x201da, order=0, oom_adj=0, oom_score_adj=0
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037367] mysqld cpuset=/ mems_allowed=0
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037370] Pid: 948, comm: mysqld Not tainted 3.2.0-29-virtual #46-Ubuntu
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037372] Call Trace:
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037382] [<ffffffff810bd5fd>] ? cpuset_print_task_mems_allowed+0x9d/0xb0
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037386] [<ffffffff81117ce1>] dump_header+0x91/0xe0
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037388] [<ffffffff81118065>] oom_kill_process+0x85/0xb0
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037391] [<ffffffff8111840a>] out_of_memory+0xfa/0x220
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037394] [<ffffffff8111de3a>] __alloc_pages_nodemask+0x7ea/0x800
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037398] [<ffffffff8165296e>] ? _raw_spin_unlock_irqrestore+0x1e/0x30
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037403] [<ffffffff81154b73>] alloc_pages_current+0xa3/0x110
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037406] [<ffffffff81114a4f>] __page_cache_alloc+0x8f/0xa0
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037409] [<ffffffff81114d4e>] ? find_get_page+0x1e/0x90
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037412] [<ffffffff81116bd2>] filemap_fault+0x212/0x3c0
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037415] [<ffffffff81136e62>] __do_fault+0x72/0x550
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037419] [<ffffffff8108ca60>] ? lock_hrtimer_base.isra.24+0x30/0x60
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037422] [<ffffffff8113a70a>] handle_pte_fault+0xfa/0x200
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037426] [<ffffffff8100648e>] ? xen_pmd_val+0xe/0x10
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037428] [<ffffffff810052e9>] ? __raw_callee_save_xen_pmd_val+0x11/0x1e
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037431] [<ffffffff8113abc8>] handle_mm_fault+0x1f8/0x350
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037434] [<ffffffff8165625b>] do_page_fault+0x14b/0x520
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037437] [<ffffffff8108d2a4>] ? hrtimer_start_range_ns+0x14/0x20
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037440] [<ffffffff8103cda5>] ? pvclock_clocksource_read+0x55/0xf0
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037444] [<ffffffff8100a640>] ? xen_clocksource_read+0x20/0x30
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037447] [<ffffffff8100a729>] ? xen_clocksource_get_cycles+0x9/0x10
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037456] [<ffffffff81093177>] ? getnstimeofday+0x57/0xe0
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037459] [<ffffffff81652eb5>] page_fault+0x25/0x30
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037460] Mem-Info:
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037462] Node 0 DMA per-cpu:
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037464] CPU 0: hi: 0, btch: 1 usd: 0
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037466] Node 0 DMA32 per-cpu:
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037468] CPU 0: hi: 186, btch: 31 usd: 123
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037471] active_anon:139853 inactive_anon:31 isolated_anon:0
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037472] active_file:38 inactive_file:169 isolated_file:0
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037473] unevictable:0 dirty:0 writeback:0 unstable:0
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037473] free:1375 slab_reclaimable:1934 slab_unreclaimable:2073
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037474] mapped:55 shmem:64 pagetables:2195 bounce:0
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037476] Node 0 DMA free:2464kB min:72kB low:88kB high:108kB active_anon:12232kB inactive_anon:0kB active_file:0kB inactive_file:12kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:14524kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:32kB slab_unreclaimable:12kB kernel_stack:0kB pagetables:24kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:3 all_unreclaimable? yes
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037484] lowmem_reserve[]: 0 597 597 597
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037487] Node 0 DMA32 free:3036kB min:3088kB low:3860kB high:4632kB active_anon:547180kB inactive_anon:124kB active_file:152kB inactive_file:664kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:611856kB mlocked:0kB dirty:0kB writeback:0kB mapped:220kB shmem:256kB slab_reclaimable:7704kB slab_unreclaimable:8280kB kernel_stack:792kB pagetables:8756kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:1943 all_unreclaimable? yes
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037495] lowmem_reserve[]: 0 0 0 0
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037498] Node 0 DMA: 8*4kB 6*8kB 5*16kB 2*32kB 3*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 1*2048kB 0*4096kB = 2464kB
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037506] Node 0 DMA32: 247*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 1*2048kB 0*4096kB = 3036kB
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037513] 279 total pagecache pages
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037514] 0 pages in swap cache
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037516] Swap cache stats: add 0, delete 0, find 0/0
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037517] Free swap = 0kB
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.037518] Total swap = 0kB
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041176] 159472 pages RAM
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041180] 8376 pages reserved
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041181] 16609 pages shared
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041182] 143523 pages non-shared
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041184] [ pid ] uid tgid total_vm rss cpu oom_adj oom_score_adj name
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041194] [ 246] 0 246 4306 49 0 0 0 upstart-udev-br
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041197] [ 250] 0 250 5365 116 0 -17 -1000 udevd
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041200] [ 300] 0 300 5364 98 0 -17 -1000 udevd
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041203] [ 301] 0 301 5364 97 0 -17 -1000 udevd
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041206] [ 393] 0 393 3795 47 0 0 0 upstart-socket-
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041209] [ 444] 0 444 1814 123 0 0 0 dhclient3
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041212] [ 617] 0 617 12487 153 0 -17 -1000 sshd
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041215] [ 629] 101 629 63428 103 0 0 0 rsyslogd
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041218] [ 636] 102 636 5952 74 0 0 0 dbus-daemon
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041221] [ 692] 0 692 3624 39 0 0 0 getty
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041224] [ 699] 0 699 3624 43 0 0 0 getty
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041227] [ 710] 0 710 3624 41 0 0 0 getty
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041230] [ 711] 0 711 3624 41 0 0 0 getty
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041236] [ 718] 0 718 3624 43 0 0 0 getty
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041239] [ 725] 0 725 1080 36 0 0 0 acpid
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041242] [ 727] 0 727 4776 59 0 0 0 cron
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041245] [ 728] 0 728 4225 40 0 0 0 atd
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041248] [ 753] 106 753 203063 19815 0 0 0 mysqld
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041251] [ 808] 103 808 46895 299 0 0 0 whoopsie
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041254] [ 857] 0 857 6274 78 0 0 0 master
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041257] [ 867] 107 867 6831 84 0 0 0 qmgr
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041260] [ 910] 0 910 76016 1435 0 0 0 apache2
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041263] [ 953] 33 953 84720 10145 0 0 0 apache2
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041266] [ 954] 33 954 90925 15531 0 0 0 apache2
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041272] [ 955] 33 955 76062 1474 0 0 0 apache2
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041275] [ 957] 33 957 81127 6426 0 0 0 apache2
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041278] [ 1065] 0 1065 22444 5138 0 0 0 /usr/share/webm
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041281] [ 1069] 0 1069 3624 41 0 0 0 getty
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041284] [ 1243] 33 1243 90163 15653 0 0 0 apache2
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041287] [ 1246] 33 1246 79452 4952 0 0 0 apache2
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041290] [ 1247] 33 1247 93679 18462 0 0 0 apache2
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041292] [ 1248] 33 1248 93574 19110 0 0 0 apache2
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041295] [ 1249] 33 1249 92189 16935 0 0 0 apache2
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041298] [ 5116] 107 5116 6790 68 0 0 0 pickup
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041301] [ 5169] 0 5169 18338 200 0 0 0 sshd
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041304] [ 5287] 1000 5287 18338 200 0 0 0 sshd
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041307] [ 5288] 1000 5288 6248 1457 0 0 0 bash
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041310] [ 5562] 0 5562 22444 5098 0 0 0 miniserv.pl
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041313] [ 5597] 0 5597 18338 201 0 0 0 sshd
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041315] [ 5687] 1000 5687 18338 201 0 0 0 sshd
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041318] [ 5688] 1000 5688 6235 1446 0 0 0 bash
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041321] [ 5784] 1000 5784 10474 92 0 0 0 sudo
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041324] [ 5785] 0 5785 3337 171 0 0 0 nano
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041327] [ 5786] 33 5786 84584 10087 0 0 0 apache2
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041330] Out of memory: Kill process 753 (mysqld) score 131 or sacrifice child
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.041396] Killed process 753 (mysqld) total-vm:812252kB, anon-rss:79260kB, file-rss:0kB
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.217049] init: mysql main process (753) killed by KILL signal
Dec 28 11:11:52 ip-10-228-98-15 kernel: [37224.218251] init: mysql main process ended, respawning
Dec 28 11:11:53 ip-10-228-98-15 kernel: [37225.185699] type=1400 audit(1356693113.390:11): apparmor="STATUS" operation="profile_replace" name="/usr/sbin/mysqld" pid=5794 comm="apparmor_parser"
Dec 28 11:11:54 ip-10-228-98-15 kernel: [37226.152344] init: mysql main process (5798) terminated with status 1
Dec 28 11:11:54 ip-10-228-98-15 kernel: [37226.152382] init: mysql main process ended, respawning
Dec 28 11:11:54 ip-10-228-98-15 kernel: [37226.768092] init: mysql post-start process (5799) terminated with status 1
Dec 28 11:11:54 ip-10-228-98-15 kernel: [37226.784475] type=1400 audit(1356693114.990:12): apparmor="STATUS" operation="profile_replace" name="/usr/sbin/mysqld" pid=5822 comm="apparmor_parser"
Dec 28 11:11:55 ip-10-228-98-15 kernel: [37226.844954] init: mysql main process (5826) terminated with status 1
Dec 28 11:11:55 ip-10-228-98-15 kernel: [37226.844991] init: mysql respawning too fast, stopped
因此，基本上 mySQL 因占用大量内存而遭到破坏，然后被判处死刑。问题是为什么？我认为 my.cnf 中的设置限制了 mySQL 可以使用的内存？另一个有趣的问题是为什么它不会再次重启？它与 apparmor 无关，我删除了它，但结果相同，但系统日志中没有 apparmor 引用。
我的.cnf：
#
# The MySQL database server configuration file.
#
# You can copy this to one of:
# - "/etc/mysql/my.cnf" to set global options,
# - "~/.my.cnf" to set user-specific options.
#
# One can use all long options that the program supports.
# Run program with --help to get a list of available options and with
# --print-defaults to see which it would actually understand and use.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html
# This will be passed to all mysql clients
# It has been reported that passwords should be enclosed with ticks/quotes
# escpecially if they contain "#" chars...
# Remember to edit /etc/mysql/debian.cnf when changing the socket location.
[client]
port = 3306
socket = /var/run/mysqld/mysqld.sock
# Here is entries for some specific programs
# The following values assume you have at least 32M ram
# This was formally known as [safe_mysqld]. Both versions are currently parsed.
[mysqld_safe]
socket = /var/run/mysqld/mysqld.sock
nice = 0
[mysqld]
#
# * Basic Settings
#
user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
lc-messages-dir = /usr/share/mysql
skip-external-locking
#
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
bind-address = 127.0.0.1
#
# * Fine Tuning
#
key_buffer = 16M
max_allowed_packet = 16M
thread_stack = 192K
thread_cache_size = 1
# This replaces the startup script and checks MyISAM tables if needed
# the first time they are touched
myisam-recover = BACKUP
max_connections = 10
#table_cache = 64
#thread_concurrency = 10
#
# * Query Cache Configuration
#
query_cache_limit = 1M
query_cache_size = 16M
#
# * Logging and Replication
#
# Both location gets rotated by the cronjob.
# Be aware that this log type is a performance killer.
# As of 5.1 you can enable the log at runtime!
#general_log_file = /var/log/mysql/mysql.log
#general_log = 1
#
# Error logging goes to syslog due to /etc/mysql/conf.d/mysqld_safe_syslog.cnf.
#
# Here you can see queries with especially long duration
#log_slow_queries = /var/log/mysql/mysql-slow.log
#long_query_time = 2
#log-queries-not-using-indexes
#
# The following can be used as easy to replay backup logs or for replication.
# note: if you are setting up a replication slave, see README.Debian about
# other settings you may need to change.
#server-id = 1
#log_bin = /var/log/mysql/mysql-bin.log
expire_logs_days = 10
max_binlog_size = 100M
#binlog_do_db = include_database_name
#binlog_ignore_db = include_database_name
#
# * InnoDB
#
# InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/.
# Read the manual for more InnoDB related options. There are many!
#
# * Security Features
#
# Read the manual, too, if you want chroot!
# chroot = /var/lib/mysql/
#
# For generating SSL certificates I recommend the OpenSSL GUI "tinyca".
#
# ssl-ca=/etc/mysql/cacert.pem
# ssl-cert=/etc/mysql/server-cert.pem
# ssl-key=/etc/mysql/server-key.pem
[mysqldump]
quick
quote-names
max_allowed_packet = 16M
[mysql]
#no-auto-rehash # faster start of mysql but no tab completition
[isamchk]
key_buffer = 16M
#
# * IMPORTANT: Additional settings that can override those from this file!
# The files must end with '.cnf', otherwise they'll be ignored.
#
!includedir /etc/mysql/conf.d/
我确实意识到这些内存设置对于 Magento 的任何性能来说都太低了，但是我在这里尝试了各种价值来获得相同的结果。克拉施！
该服务器是一个运行 Ubuntu 12.04 x64 的 EC2 微型实例，我不期待超快的速度（没有生产用途），但至少我应该能够配置它，这样它就不会一直崩溃。我有另一个在 32 位 Ubuntu 上运行的 EC2 微型实例，而 mySQL 服务器从未在该实例上崩溃过。它可能与 32 位和 64 位 Ubuntu 有关吗？
如您所见，有很多问题但知识有限，感谢任何指点。我会及时向大家发布。