AWS WordPressサイト-OOMがApacheを殺す
この質問は元々StackOverflow.comで行われたもので、より適切なServerFault.comサイトに複製しました。私が閉じることに投票した元の質問は、見つけることができます ここ
小規模でトラフィックが少ないWordPressブログがAWSでホストされています。残念ながら、週に1回程度、ウェブサイトが利用できなくなり、ウェブサイトにアクセスしようとすると、接続がタイムアウトするまでユーザーがハングします。また、これらのダウンタイム中は、サーバーが再起動されるまでSSH経由でサーバーにアクセスできません。サーバーは、インスタンスを再起動するとすぐに回復します。
AWS EC2ログの最後の行（30,000文字の制限によりすべてのログを投稿できません）：
[1079988.125918] Out of memory: Kill process 32620 (httpd) score 16 or sacrifice child
[1079988.130913] Killed process 32620 (httpd) total-vm:510348kB, anon-rss:32328kB, file-rss:0kB
[1079996.872570] httpd invoked oom-killer: gfp_mask=0x24280ca, order=0, oom_score_adj=0
[1079996.887776] httpd cpuset=/ mems_allowed=0
[1079996.892671] CPU: 0 PID: 374 Comm: httpd Tainted: G E 4.4.5-15.26.amzn1.x86_64 #1
[1079996.896664] Hardware name: Xen HVM domU, BIOS 4.2.Amazon 12/07/2015
[1079996.896664] 0000000000000000 ffff88002f66bb58 ffffffff812c88ef ffff88002f66bd40
[1079996.896664] 0000000000000000 ffff88002f66bbe8 ffffffff811cdc8d 0000000000000001
[1079996.896664] ffffffff810b2c61 0000000000000000 0000000000000010 ffffffff817d07f9
[1079996.896664] Call Trace:
[1079996.896664] [<ffffffff812c88ef>] dump_stack+0x63/0x84
[1079996.896664] [<ffffffff811cdc8d>] dump_header+0x5e/0x1d8
[1079996.896664] [<ffffffff810b2c61>] ? __raw_callee_save___pv_queued_spin_unlock+0x11/0x20
[1079996.896664] [<ffffffff811634d5>] oom_kill_process+0x205/0x3d0
[1079996.896664] [<ffffffff81163b35>] out_of_memory+0x435/0x480
[1079996.896664] [<ffffffff81168bee>] __alloc_pages_nodemask+0x91e/0xa60
[1079996.896664] [<ffffffff811ae5e5>] alloc_pages_vma+0xb5/0x210
[1079996.896664] [<ffffffff8118e296>] handle_mm_fault+0x13a6/0x1870
[1079996.896664] [<ffffffff810b2c61>] ? __raw_callee_save___pv_queued_spin_unlock+0x11/0x20
[1079996.896664] [<ffffffff810922c2>] ? finish_task_switch+0x72/0x1d0
[1079996.896664] [<ffffffff8105ea23>] __do_page_fault+0x183/0x3f0
[1079996.896664] [<ffffffff8105ecb2>] do_page_fault+0x22/0x30
[1079996.896664] [<ffffffff814de858>] page_fault+0x28/0x30
[1079996.958270] Mem-Info:
[1079996.959270] active_anon:457775 inactive_anon:13 isolated_anon:0
[1079996.959270] active_file:16 inactive_file:106 isolated_file:0
[1079996.959270] unevictable:0 dirty:0 writeback:0 unstable:0
[1079996.959270] slab_reclaimable:2369 slab_unreclaimable:10892
[1079996.959270] mapped:24 shmem:35 pagetables:33000 bounce:0
[1079996.959270] free:3686 free_pcp:68 free_cma:0
[1079996.973173] Node 0 DMA free:7976kB min:40kB low:48kB high:60kB active_anon:6348kB inactive_anon:0kB active_file:4kB inactive_file:24kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15988kB managed:15904kB mlocked:0kB dirty:0kB writeback:0kB mapped:8kB shmem:0kB slab_reclaimable:72kB slab_unreclaimable:268kB kernel_stack:0kB pagetables:1036kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:168 all_unreclaimable? yes
[1079996.991168] lowmem_reserve[]: 0 1984 1984 1984
[1079996.993371] Node 0 DMA32 free:6768kB min:5584kB low:6980kB high:8376kB active_anon:1824752kB inactive_anon:52kB active_file:60kB inactive_file:400kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:2080768kB managed:2035632kB mlocked:0kB dirty:0kB writeback:0kB mapped:88kB shmem:140kB slab_reclaimable:9404kB slab_unreclaimable:43300kB kernel_stack:3920kB pagetables:130964kB unstable:0kB bounce:0kB free_pcp:272kB local_pcp:272kB free_cma:0kB writeback_tmp:0kB pages_scanned:2808 all_unreclaimable? yes
[1079997.012134] lowmem_reserve[]: 0 0 0 0
[1079997.014077] Node 0 DMA: 30*4kB (ME) 71*8kB (UM) 26*16kB (UME) 3*32kB (ME) 0*64kB 1*128kB (E) 2*256kB (ME) 2*512kB (ME) 1*1024kB (E) 2*2048kB (UM) 0*4096kB = 7984kB
[1079997.021833] Node 0 DMA32: 478*4kB (UME) 55*8kB (UM) 210*16kB (UM) 31*32kB (M) 1*64kB (M) 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 6768kB
[1079997.028501] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
[1079997.032184] 160 total pagecache pages
[1079997.033858] 0 pages in swap cache
[1079997.035455] Swap cache stats: add 0, delete 0, find 0/0
[1079997.037793] Free swap = 0kB
[1079997.039117] Total swap = 0kB
[1079997.040511] 524189 pages RAM
[1079997.041780] 0 pages HighMem/MovableOnly
[1079997.043474] 11305 pages reserved
[1079997.044872] [ pid ] uid tgid total_vm rss nr_ptes nr_pmds swapents oom_score_adj name
[1079997.048548] [ 1524] 0 1524 2866 229 12 3 0 -1000 udevd
[1079997.052366] [ 1647] 0 1647 2865 213 11 3 0 -1000 udevd
[1079997.056081] [ 1648] 0 1648 2865 210 11 3 0 -1000 udevd
[1079997.059637] [ 2045] 0 2045 2340 123 10 3 0 0 dhclient
[1079997.063283] [ 2097] 0 2097 28018 106 25 3 0 -1000 auditd
[1079997.067016] [ 2118] 0 2118 61865 375 25 3 0 0 rsyslogd
[1079997.070879] [ 2140] 0 2140 1095 37 8 3 0 0 rngd
[1079997.074484] [ 2158] 32 2158 8823 97 22 3 0 0 rpcbind
[1079997.078205] [ 2179] 29 2179 9965 201 24 3 0 0 rpc.statd
[1079997.081954] [ 2210] 81 2210 5448 61 15 3 0 0 dbus-daemon
[1079997.085861] [ 2339] 0 2339 19458 203 40 3 0 -1000 sshd
[1079997.089500] [ 2361] 38 2361 7322 140 18 3 0 0 ntpd
[1079997.093148] [ 2654] 0 2654 22245 463 45 3 0 0 sendmail
[1079997.096960] [ 2663] 51 2663 20109 369 40 4 0 0 sendmail
[1079997.100976] [ 2678] 0 2678 102872 1914 200 3 0 0 httpd
[1079997.104736] [ 2689] 0 2689 29880 146 15 3 0 0 crond
[1079997.108453] [ 2703] 0 2703 4267 41 13 3 0 0 atd
[1079997.112100] [ 2733] 0 2733 1615 31 8 3 0 0 agetty
[1079997.115895] [ 2735] 0 2735 1078 24 8 3 0 0 mingetty
[1079997.119835] [ 2738] 0 2738 1078 24 8 3 0 0 mingetty
[1079997.123661] [ 2740] 0 2740 1078 24 7 3 0 0 mingetty
[1079997.127430] [ 2742] 0 2742 1078 24 8 3 0 0 mingetty
[1079997.131420] [ 2744] 0 2744 1078 23 8 3 0 0 mingetty
[1079997.135291] [ 2746] 0 2746 1078 24 8 3 0 0 mingetty
[1079997.139070] [32214] 48 32214 126502 7229 209 3 0 0 httpd
[1079997.142642] [32297] 48 32297 125281 6111 207 3 0 0 httpd
[1079997.146286] [32310] 48 32310 125754 6561 208 3 0 0 httpd
[1079997.150023] [32346] 48 32346 125990 6820 208 3 0 0 httpd
[1079997.153576] [32365] 48 32365 127220 7837 210 3 0 0 httpd
[1079997.157241] [32369] 48 32369 125991 6820 208 3 0 0 httpd
[1079997.160923] [32395] 48 32395 125282 6129 207 3 0 0 httpd
[1079997.164515] [32498] 48 32498 125998 6758 208 3 0 0 httpd
[1079997.168490] [32515] 48 32515 125281 6111 207 3 0 0 httpd
[1079997.172046] [32575] 48 32575 125732 6475 208 3 0 0 httpd
[1079997.175868] [32578] 48 32578 125683 6508 207 3 0 0 httpd
[1079997.179602] [32584] 48 32584 125731 6561 208 3 0 0 httpd
[1079997.183372] [32598] 48 32598 125683 6508 207 3 0 0 httpd
[1079997.187140] [32603] 48 32603 125731 6561 208 3 0 0 httpd
[1079997.190715] [32608] 48 32608 125683 6508 207 3 0 0 httpd
[1079997.194454] [32612] 48 32612 126566 7496 209 3 0 0 httpd
[1079997.198263] [32625] 48 32625 125524 6305 207 3 0 0 httpd
[1079997.201863] [32635] 48 32635 125731 6561 208 3 0 0 httpd
[1079997.205449] [32649] 48 32649 125990 6748 208 3 0 0 httpd
[1079997.209316] [32650] 48 32650 107262 6519 206 3 0 0 httpd
[1079997.213170] [32652] 48 32652 127395 7886 211 3 0 0 httpd
[1079997.216906] [32658] 48 32658 125729 6527 208 3 0 0 httpd
[1079997.220644] [32661] 48 32661 108843 7773 210 3 0 0 httpd
[1079997.224418] [32666] 48 32666 125282 6111 207 3 0 0 httpd
[1079997.228078] [32669] 48 32669 126892 7484 210 3 0 0 httpd
[1079997.231832] [32675] 48 32675 125706 6520 207 3 0 0 httpd
[1079997.235511] [32676] 48 32676 125683 6508 207 3 0 0 httpd
[1079997.239227] [32681] 48 32681 125684 6508 207 3 0 0 httpd
[1079997.243019] [32691] 48 32691 125993 6747 208 3 0 0 httpd
[1079997.246836] [32696] 48 32696 125683 6507 207 3 0 0 httpd
[1079997.250732] [32698] 48 32698 126371 6954 209 3 0 0 httpd
[1079997.254287] [32700] 48 32700 107752 6734 207 3 0 0 httpd
[1079997.258018] [32703] 48 32703 106347 5553 205 3 0 0 httpd
[1079997.261647] [32714] 48 32714 125684 6508 207 3 0 0 httpd
[1079997.265446] [32723] 48 32723 125731 6561 208 3 0 0 httpd
[1079997.269066] [ 307] 48 307 125685 6506 207 3 0 0 httpd
[1079997.272679] [ 314] 48 314 108660 7632 209 3 0 0 httpd
[1079997.276452] [ 319] 48 319 107752 6723 207 3 0 0 httpd
[1079997.280364] [ 320] 48 320 107240 6427 206 3 0 0 httpd
[1079997.284027] [ 323] 48 323 107888 6912 208 3 0 0 httpd
[1079997.287595] [ 324] 48 324 107122 6264 206 3 0 0 httpd
[1079997.291243] [ 325] 48 325 122406 7539 209 3 0 0 httpd
[1079997.294995] [ 326] 48 326 108274 7130 208 3 0 0 httpd
[1079997.298756] [ 327] 48 327 124978 7732 210 3 0 0 httpd
[1079997.302330] [ 329] 48 329 108274 7267 208 3 0 0 httpd
[1079997.306007] [ 333] 48 333 106928 6052 206 3 0 0 httpd
[1079997.309818] [ 334] 48 334 105747 4938 203 3 0 0 httpd
[1079997.313613] [ 338] 48 338 108539 7521 209 3 0 0 httpd
[1079997.317252] [ 339] 48 339 107816 6838 208 3 0 0 httpd
[1079997.320966] [ 340] 48 340 108361 7341 209 3 0 0 httpd
[1079997.324587] [ 342] 48 342 107944 6986 208 3 0 0 httpd
[1079997.328421] [ 343] 48 343 103541 2605 199 3 0 0 httpd
[1079997.331943] [ 344] 48 344 106288 5479 205 3 0 0 httpd
[1079997.335650] [ 346] 48 346 106493 5678 205 3 0 0 httpd
[1079997.339365] [ 347] 48 347 108326 7310 209 3 0 0 httpd
[1079997.343168] [ 349] 48 349 106412 5579 205 3 0 0 httpd
[1079997.346819] [ 350] 48 350 106612 5832 205 3 0 0 httpd
[1079997.350423] [ 351] 48 351 107440 6484 207 3 0 0 httpd
[1079997.354093] [ 352] 48 352 106984 6133 206 3 0 0 httpd
[1079997.357822] [ 354] 48 354 107122 6265 206 3 0 0 httpd
[1079997.361467] [ 355] 48 355 103541 2604 199 3 0 0 httpd
[1079997.365074] [ 358] 48 358 103541 2605 199 3 0 0 httpd
[1079997.368805] [ 359] 48 359 106475 5660 205 3 0 0 httpd
[1079997.372852] [ 360] 48 360 104710 3796 201 3 0 0 httpd
[1079997.376601] [ 370] 48 370 103538 2622 199 3 0 0 httpd
[1079997.380201] [ 372] 48 372 103538 2622 199 3 0 0 httpd
[1079997.383966] [ 373] 48 373 107752 6733 207 3 0 0 httpd
[1079997.387998] [ 374] 48 374 108539 7520 209 3 0 0 httpd
[1079997.391913] [ 375] 48 375 103541 2604 199 3 0 0 httpd
[1079997.395537] [ 376] 48 376 103538 2626 199 3 0 0 httpd
[1079997.399174] [ 378] 48 378 106467 5646 205 3 0 0 httpd
[1079997.402981] [ 381] 48 381 107952 6967 208 3 0 0 httpd
[1079997.406805] [ 383] 48 383 108338 7328 209 3 0 0 httpd
[1079997.410374] [ 385] 48 385 105068 4224 202 3 0 0 httpd
[1079997.414010] [ 388] 48 388 104866 4047 202 3 0 0 httpd
[1079997.417701] [ 392] 48 392 105881 5036 204 3 0 0 httpd
[1079997.421384] [ 394] 48 394 106347 5540 205 3 0 0 httpd
[1079997.425365] [ 396] 48 396 103538 2626 199 3 0 0 httpd
[1079997.429044] [ 407] 48 407 103838 2961 200 3 0 0 httpd
[1079997.432577] [ 412] 48 412 103542 2605 199 3 0 0 httpd
[1079997.436201] [ 413] 48 413 105079 4262 202 3 0 0 httpd
[1079997.439868] [ 416] 48 416 103541 2605 199 3 0 0 httpd
[1079997.443501] [ 422] 48 422 103541 2604 199 3 0 0 httpd
[1079997.447093] [ 424] 48 424 103540 2637 199 3 0 0 httpd
[1079997.450727] [ 426] 48 426 103542 2604 199 3 0 0 httpd
[1079997.454398] [ 427] 48 427 103541 2604 199 3 0 0 httpd
[1079997.458434] [ 428] 48 428 103538 2622 199 3 0 0 httpd
[1079997.463763] [ 429] 48 429 103541 2604 199 3 0 0 httpd
[1079997.467592] [ 437] 48 437 103538 2627 199 3 0 0 httpd
[1079997.471172] [ 438] 48 438 104324 3456 201 3 0 0 httpd
[1079997.474751] [ 439] 48 439 103541 2604 199 3 0 0 httpd
[1079997.478432] [ 440] 48 440 103545 2622 199 3 0 0 httpd
[1079997.482044] [ 441] 48 441 103539 2622 199 3 0 0 httpd
[1079997.485780] [ 442] 48 442 106474 5667 205 3 0 0 httpd
[1079997.489572] [ 445] 48 445 103547 2620 199 3 0 0 httpd
[1079997.493165] [ 448] 48 448 103541 2604 199 3 0 0 httpd
[1079997.496719] [ 449] 48 449 104500 3638 201 3 0 0 httpd
[1079997.500255] [ 450] 48 450 106208 5364 204 3 0 0 httpd
[1079997.503768] [ 468] 48 468 103613 2733 199 3 0 0 httpd
[1079997.507327] [ 469] 48 469 103538 2622 199 3 0 0 httpd
[1079997.511042] [ 470] 48 470 103541 2604 199 3 0 0 httpd
[1079997.514670] [ 471] 48 471 103541 2604 199 3 0 0 httpd
[1079997.518298] [ 472] 48 472 103542 2605 199 3 0 0 httpd
[1079997.522039] [ 480] 48 480 104314 3471 201 3 0 0 httpd
[1079997.525663] [ 481] 48 481 103610 2670 199 3 0 0 httpd
[1079997.529538] [ 482] 48 482 103541 2604 199 3 0 0 httpd
[1079997.533280] [ 483] 48 483 103542 2604 199 3 0 0 httpd
[1079997.536999] [ 484] 48 484 103538 2622 199 3 0 0 httpd
[1079997.540651] [ 485] 48 485 103538 2622 199 3 0 0 httpd
[1079997.544204] [ 486] 48 486 104094 3224 200 3 0 0 httpd
[1079997.547808] [ 488] 48 488 119730 2929 201 3 0 0 httpd
[1079997.551370] [ 489] 48 489 103538 2622 199 3 0 0 httpd
[1079997.554962] [ 490] 48 490 104808 3968 202 3 0 0 httpd
[1079997.558875] [ 491] 48 491 103538 2622 199 3 0 0 httpd
[1079997.562490] [ 494] 48 494 104059 3199 200 3 0 0 httpd
[1079997.566339] [ 495] 48 495 104143 3232 200 3 0 0 httpd
[1079997.570045] [ 501] 48 501 103564 2562 199 3 0 0 httpd
[1079997.573871] [ 502] 48 502 104707 3771 201 3 0 0 httpd
[1079997.577369] [ 503] 48 503 103538 2621 199 3 0 0 httpd
[1079997.580897] [ 504] 48 504 103541 2609 199 3 0 0 httpd
[1079997.584364] [ 505] 48 505 103539 2621 199 3 0 0 httpd
[1079997.588037] [ 506] 48 506 103545 2621 199 3 0 0 httpd
[1079997.591946] [ 507] 48 507 103541 2604 199 3 0 0 httpd
[1079997.595820] [ 508] 48 508 103538 2622 199 3 0 0 httpd
[1079997.599555] [ 509] 48 509 103541 2604 199 3 0 0 httpd
[1079997.603102] [ 510] 48 510 103475 2562 199 3 0 0 httpd
[1079997.609123] [ 511] 48 511 103539 2622 199 3 0 0 httpd
[1079997.613009] [ 512] 48 512 103281 2335 199 3 0 0 httpd
[1079997.616695] [ 513] 48 513 103475 2562 199 3 0 0 httpd
[1079997.620272] [ 514] 48 514 103541 2604 199 3 0 0 httpd
[1079997.623949] [ 515] 48 515 103475 2562 199 3 0 0 httpd
[1079997.627601] [ 516] 48 516 103066 2051 198 3 0 0 httpd
[1079997.631257] [ 517] 48 517 103285 2307 199 3 0 0 httpd
[1079997.634944] [ 518] 48 518 103539 2622 199 3 0 0 httpd
[1079997.638875] [ 519] 48 519 103484 2517 199 3 0 0 httpd
[1079997.642467] [ 520] 48 520 103541 2601 199 3 0 0 httpd
[1079997.646281] [ 521] 48 521 103564 2562 199 3 0 0 httpd
[1079997.650000] [ 522] 48 522 103254 2242 199 3 0 0 httpd
[1079997.654227] [ 523] 48 523 103541 2601 199 3 0 0 httpd
[1079997.657861] [ 524] 48 524 102968 2025 198 3 0 0 httpd
[1079997.662169] [ 525] 48 525 103433 2411 199 3 0 0 httpd
[1079997.666436] [ 526] 48 526 102968 2050 198 3 0 0 httpd
[1079997.670950] [ 527] 48 527 103254 2252 199 3 0 0 httpd
[1079997.676349] [ 528] 48 528 103281 2350 199 3 0 0 httpd
[1079997.680095] [ 529] 48 529 103538 2561 199 3 0 0 httpd
[1079997.683947] [ 530] 48 530 103173 2126 198 3 0 0 httpd
[1079997.687608] [ 531] 48 531 103228 2262 199 3 0 0 httpd
[1079997.691466] [ 532] 48 532 103475 2515 199 3 0 0 httpd
[1079997.694988] [ 533] 48 533 103173 2119 198 3 0 0 httpd
[1079997.698754] [ 534] 48 534 102975 1973 198 3 0 0 httpd
[1079997.702324] [ 535] 48 535 103434 2409 199 3 0 0 httpd
[1079997.705935] [ 536] 0 536 102872 1915 192 3 0 0 httpd
[1079997.709734] [ 537] 48 537 102968 2032 198 3 0 0 httpd
[1079997.713367] [ 538] 48 538 102873 1926 198 3 0 0 httpd
[1079997.717141] [ 539] 48 539 102872 1922 196 3 0 0 httpd
[1079997.720839] [ 540] 48 540 102975 1973 198 3 0 0 httpd
[1079997.724457] [ 541] 0 541 102872 1915 192 3 0 0 httpd
[1079997.728106] [ 542] 48 542 102872 1915 193 3 0 0 httpd
[1079997.731629] [ 543] 48 543 102872 1915 193 3 0 0 httpd
[1079997.735163] [ 544] 48 544 102872 1915 193 3 0 0 httpd
[1079997.738927] Out of memory: Kill process 32652 (httpd) score 15 or sacrifice child
[1079997.742215] Killed process 32652 (httpd) total-vm:509580kB, anon-rss:31536kB, file-rss:8kB
ログを考えると、メモリ使用量が少ないことが関係していると思いますが、インスタンスをより大きなインスタンスにアップグレードしても、問題の発生を防ぐことはできません。また、このサイトのトラフィックは非常に少ないため（<50ユーザー/週）、現在実行されているt1-mediumよりもはるかに大きなサーバーが必要になるのは意味がありません。
ソフトウェアバージョン：
PHP（php --version）：
PHP 5.6.21 (cli) (built: May 2 2016 23:27:53)
Copyright (c) 1997-2016 The PHP Group
Zend Engine v2.6.0, Copyright (c) 1998-2016 Zend Technologies
MySQL（mysql --version）：
mysql Ver 14.14 Distrib 5.5.46, for Linux (x86_64) using readline 5.1
Apache（apachectl -V）：
Server version: Apache/2.4.18 (Amazon)
Server built: Mar 7 2016 22:32:11
Server's Module Magic Number: 20120211:52
Server loaded: APR 1.5.1, APR-UTIL 1.4.1
Compiled using: APR 1.5.1, APR-UTIL 1.4.1
Architecture: 64-bit
Server MPM: prefork
threaded: no
forked: yes (variable process count)
Server compiled with....
-D APR_HAS_SENDFILE
-D APR_HAS_MMAP
-D APR_HAVE_IPV6 (IPv4-mapped addresses enabled)
-D APR_USE_SYSVSEM_SERIALIZE
-D APR_USE_PTHREAD_SERIALIZE
-D SINGLE_LISTEN_UNSERIALIZED_ACCEPT
-D APR_HAS_OTHER_CHILD
-D AP_HAVE_RELIABLE_PIPED_LOGS
-D DYNAMIC_MODULE_LIMIT=256
-D HTTPD_ROOT="/etc/httpd"
-D SUEXEC_BIN="/usr/sbin/suexec"
-D DEFAULT_PIDLOG="/var/run/httpd/httpd.pid"
-D DEFAULT_SCOREBOARD="logs/Apache_runtime_status"
-D DEFAULT_ERRORLOG="logs/error_log"
-D AP_TYPES_CONFIG_FILE="conf/mime.types"
-D SERVER_CONFIG_FILE="conf/httpd.conf"
WordPress（grep wp_version "$WPDIR/wp-includes/version.php"）：
* @global string $wp_version
$wp_version = '4.4.3';
free -mコマンド出力：
サーバーを再起動しましたが、エラーは現在サーバーに影響を与えていないことに注意してください。したがって、以下の出力は、エラーが発生したときからの出力ではなく、サーバーを再起動した後の出力です。
total used free shared buffers cached
Mem: 2003 741 1261 0 21 469
-/+ buffers/cache: 250 1752
Swap:
0 0 0
システムがOOMキラーを呼び出したとき、161のhttpdプロセスを実行しているように見えます。これは、週に50ユーザー未満になるシステムには少し過剰なようです。
私が最初にすることは、システムが生成して存続させるhttpdプロセスの数を減らすことです。
これを行うには、StartServers、MinSpareServers、MaxSpareServers、ServerLimitなどの値を調整します（詳細については、 Apacheドキュメント を参照してくださいそれらのそれぞれおよびそれ以上）。
これを適切に行うには、袖をまくり上げて、 科学的方法 を使用して手を汚す必要があります。または、ServerLimitをランダムに減らして、何が起こるかを確認することもできます。
上記のIainがApacheを強制終了しているので、最近同様の問題が発生しました。最初の解決策は、Apacheの負荷を軽減することでした...特にwp-cron.phpファイル。
wordpressで実行されているファイルをすべてのページをクリックするたびに無効にし、手動cronを作成すると、サーバーから多くの負荷が削除されました： http://www.inmotionhosting.com/support/ウェブサイト/ワードプレス/無効化-the-wp-cronphp-in-wordpress
それに加えて、Apacheのチューニングはこれを解決するのに最も効果的でした..私のものは次のようなものになりました：
StartServers 5
MinSpareServers 5
MaxSpareServers 10
MaxClients 50
MaxRequestsPerChild 200
同じ種類のトラフィック負荷で同じ問題が発生していました。ただし、無効にしたばかりですJetpackそしてそれは魅力のように機能しているようです-JetPackからの追加のクエリが問題を引き起こしているのではないかと思いますか？