site AWS WordPress - OOM mata Apache

Question

Esta pergunta foi originalmente feita no StackOverflow.com e eu a copiei para o site ServerFault.com mais apropriado. A questão original, que eu votei para fechar, pode ser encontrada aqui

Eu tenho um pequeno blog WordPress de baixo tráfego hospedado na AWS. Infelizmente, aproximadamente uma vez por semana, o site fica indisponível e a tentativa de acessar o site deixa os usuários em suspenso até que a conexão expire. Eu também não consigo acessar o servidor via SSH durante esses downtimes, até que o servidor seja reiniciado. Ele sempre se recupera instantaneamente após a reinicialização da instância.

Últimas linhas do log do AWS EC2 (o limite de 30.000 caracteres impede postar tudo):

[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

Eu acredito que tenha a ver com o uso de pouca memória, dado o log, no entanto, atualizar a instância para uma maior não impede que o problema ocorra. Além disso, o site tem tráfego extremamente baixo (< 50 usuários / semana), portanto, não faz sentido precisar de um servidor muito maior do que o t1-medium em que ele está sendo executado.

Versões de software:

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';

% saída do comandofree -m:

Por favor, note que reiniciei o servidor e o erro não está afetando o servidor no momento. Portanto, a saída abaixo não é a saída de quando o erro ocorreu, mas depois de reiniciar o servidor.

             total       used       free     shared    buffers     cached
Mem:          2003        741       1261          0         21        469
-/+ buffers/cache:        250       1752
Swap:     

   0          0          0

    

Answer 1

Quando o sistema invocou o killer da OOM, parece que você está executando 161 processos httpd, o que parece ser um pouco excessivo para um sistema que recebe < 50 usuários / semana.

A primeira coisa que eu faria é reduzir o número de processos do httpd que seu sistema irá gerar e manter vivo

Para isso, ajuste os valores de StartServers , MinSpareServers , MaxSpareServers , ServerLimit , etc (veja o Documentação do Apache para detalhes sobre cada um e mais).

Para fazer isso corretamente, você terá que arregaçar as mangas e sujar as mãos com o auxílio de Método Científico ou você pode reduzir aleatoriamente o ServerLimit e ver o que acontece.

    

Answer 2

Como Iain descreveu acima, o módulo do kernel está matando o apache Recentemente eu tive problemas semelhantes, minha primeira solução foi aliviar a carga no apache ... particularmente no arquivo wp-cron.php.

Desabilitando o arquivo em execução no wordpress em cada clique de cada página e fazendo com que um cron manual tenha removido muita carga do servidor: link

Além disso, o ajuste do apache foi mais eficaz para resolver isso ... o meu acabou sendo algo como:

StartServers        5
MinSpareServers     5
MaxSpareServers     10
MaxClients          50
MaxRequestsPerChild 200

    

Answer 3

Eu estava correndo para o mesmo problema com o mesmo tipo de carga de tráfego. No entanto, eu acabei de desativar o Jetpack e ele parece estar funcionando como um encanto - estou pensando se as consultas extras do JetPack estão causando problemas?