我在linode中部署一个Web服务器，使用nginx作为代理服务器。我检查nginx日志在日志中发现太多499和504错误半小时。日志：
186.178.211.41~-~23/Nov/2014:19:42:41 +0000~2014-11-23T19:42:41+00:00~GET /category/?format=json&device_uid=mzHPz5IlTnd35XsLIcM6RwwAil4=&language_code=es-mx HTTP/1.1~499~0~-~NativeHost~15.484~-~.
186.178.211.41~-~23/Nov/2014:19:42:41 +0000~2014-11-23T19:42:41+00:00~GET /hot_search_words/?format=json&device_id=mzHPz5IlTnd35XsLIcM6RwwAil4=&language_code=es-mx HTTP/1.1~499~0~-~NativeHost~15.491~-~.
92.244.224.127~-~23/Nov/2014:19:42:44 +0000~2014-11-23T19:42:44+00:00~GET /artists/ru-RU/hot/?format=json&device_id=trXB2a4sVjugB3g6400Ivf6JVq0=&language_code=ru-ru HTTP/1.1~499~0~file:///Applications/Install/92C003B2-2C7B-499E-8533-F580EF1E5FE8/Install/~NativeHost~3.772~-~.
178.207.247.88~-~23/Nov/2014:19:42:44 +0000~2014-11-23T19:42:44+00:00~GET /artists/ru-RU/hot/?format=json&device_id=p3O/TpqU7tPBrw4QJamBI91FuGo=&language_code=ru-ru HTTP/1.1~499~0~file:///Applications/Install/92C003B2-2C7B-499E-8533-F580EF1E5FE8/Install/~NativeHost~18.669~-~.
189.167.212.240~-~23/Nov/2014:19:42:49 +0000~2014-11-23T19:42:49+00:00~GET /search/soda%20sterio/?format=json&device_id=a7xk4UCiPSp52cla6hA8glcY/xc=&language_code=es-mx HTTP/1.1~499~0~file:///Applications/Install/92C003B2-2C7B-499E-8533-F580EF1E5FE8/Install/~NativeHost~33.372~-~.
187.127.153.104~-~23/Nov/2014:19:42:49 +0000~2014-11-23T19:42:49+00:00~GET /artists/pt-BR/hot/?format=json&device_id=nUHU4vR/N1zrqXZGtz3kEv44H40=&language_code=pt-br HTTP/1.1~499~0~file:///Applications/Install/92C003B2-2C7B-499E-8533-F580EF1E5FE8/Install/~NativeHost~2.788~-~.
178.207.247.88~-~23/Nov/2014:19:42:51 +0000~2014-11-23T19:42:51+00:00~GET /artists/ru-RU/hot/?format=json&device_id=p3O/TpqU7tPBrw4QJamBI91FuGo=&language_code=ru-ru HTTP/1.1~499~0~file:///Applications/Install/92C003B2-2C7B-499E-8533-F580EF1E5FE8/Install/~NativeHost~2.780~-~.
201.160.162.251~-~23/Nov/2014:19:42:51 +0000~2014-11-23T19:42:51+00:00~GET /category/?format=json&device_uid=3R9U1EC9t9OPyCG+xx587jawrA4=&language_code=es-mx HTTP/1.1~499~0~-~NativeHost~37.645~-~.
201.160.162.251~-~23/Nov/2014:19:42:51 +0000~2014-11-23T19:42:51+00:00~GET /hot_search_words/?format=json&device_id=3R9U1EC9t9OPyCG+xx587jawrA4=&language_code=es-mx HTTP/1.1~499~0~-~NativeHost~37.658~-~.
191.40.56.15~-~23/Nov/2014:19:42:52 +0000~2014-11-23T19:42:52+00:00~GET /download_search/Coldplay/?format=json&device_id=BstZoStXYr9n7dta3lH87LZ+JdQ=&language_code=pt-br HTTP/1.1~200~36502~-~NativeHost~60.150~0.151~.
179.176.171.88~-~23/Nov/2014:19:42:53 +0000~2014-11-23T19:42:53+00:00~GET /download_search/mc%20daleste/?format=json&device_id=khIXpv8FfabUN+rP3W1zryMuKTg=&language_code=pt-br HTTP/1.1~499~0~-~NativeHost~27.803~-~.
200.49.206.194~-~23/Nov/2014:19:42:57 +0000~2014-11-23T19:42:57+00:00~GET /hot_search_words/?format=json&device_id=LXpdPQFTQvlpsxQoFx7Wc8lu3Ig=&language_code=es-mx HTTP/1.1~499~0~-~NativeHost~44.730~-~.
200.49.206.196~-~23/Nov/2014:19:42:57 +0000~2014-11-23T19:42:57+00:00~GET /category/?format=json&device_uid=LXpdPQFTQvlpsxQoFx7Wc8lu3Ig=&language_code=es-mx HTTP/1.1~499~0~-~NativeHost~42.503~-~.
82.54.64.173~-~23/Nov/2014:19:42:57 +0000~2014-11-23T19:42:57+00:00~GET /search_song/Eminem/?format=json&device_id=93rtmqeKtFWwLKryT6oUs+1vxuc=&language_code=it-it HTTP/1.1~499~0~-~NativeHost~25.195~-~.
79.30.49.69~-~23/Nov/2014:19:42:58 +0000~2014-11-23T19:42:58+00:00~GET /category/11/?format=json&device_id=hy/IVVuDP3UIxg4r3ht7mHJ9ZTU=&language_code=it-it HTTP/1.1~499~0~-~NativeHost~25.384~-~.
31.22.48.80~-~23/Nov/2014:19:42:59 +0000~2014-11-23T19:42:59+00:00~GET /download_search/Iggy%20Azalea/?format=json&device_id=0HXsA4AwHsE+j9Bx0I6gtiLV63A=&language_code=it-it HTTP/1.1~499~0~-~NativeHost~38.689~-~.
186.16.172.168~-~23/Nov/2014:19:43:00 +0000~2014-11-23T19:43:00+00:00~GET /category/?format=json&device_uid=Fv+ux25HB4g+0u7ANpmEjSpN9U4=&language_code=es-mx HTTP/1.1~499~0~-~NativeHost~20.327~-~.
186.16.172.168~-~23/Nov/2014:19:43:00 +0000~2014-11-23T19:43:00+00:00~GET /hot_search_words/?format=json&device_id=Fv+ux25HB4g+0u7ANpmEjSpN9U4=&language_code=es-mx HTTP/1.1~499~0~-~NativeHost~20.317~-~.
83.149.35.184~-~23/Nov/2014:19:43:01 +0000~2014-11-23T19:43:01+00:00~GET /hot_search_words/?format=json&device_id=Srf/h9PjMl9IqO/RRW+R63f/fM4=&language_code=ru-ru HTTP/1.1~499~0~-~NativeHost~26.999~-~.
这是正常时的nginx日志：
99.20.177.137~ - 〜24 / Nov / 2014：06：33：08 + 0000~2014-11-24T06：33：08 + 00：00~GET / category /？format = json＆amp; device_uid = aMjSSmVjO89d + pCPIpDCDmcwhcU =安培; LANGUAGE_CODE = EN-US HTTP / 1.1〜200〜1217〜 - 〜NativeHost〜0.050〜0.050〜。 99.20.177.137~ - 〜24 / Nov / 2014：06：33：08 + 0000~2014-11-24T06：33：08 + 00：00~GET / hot_search_words /？format = json＆amp; device_id = aMjSSmVjO89d + pCPIpDCDmcwhcU =＆amp; ; LANGUAGE_CODE = EN-US HTTP / 1.1〜200〜1036〜 - 〜NativeHost〜0.049〜0.049〜。 213.119.140.83~ - 〜24 / Nov / 2014：06：33：08 + 0000~2014-11-24T06：33：08 + 00：00~GET / category / 5 /？format = json＆amp; device_id = FxDpCbvaAT3cm97imBFribqr4dI =＆amp; ; LANGUAGE_CODE = NL-NL HTTP / 1.1〜200〜3359〜 - 〜NativeHost〜0.024〜0.024〜。 201.29.210.76~ - 〜24 / Nov / 2014：06：33：11 + 0000~2014-11-24T06：33：11 + 00：00~GET / category /？format = json＆amp; device_uid = 9dcT9DnwXug7R4KHGZvC2PReGkg =＆amp; language_code = PT-BR HTTP / 1.1〜200〜1217〜 - 〜NativeHost〜0.008〜0.008〜。 201.29.210.76~ - 〜24 / Nov / 2014：06：33：11 + 0000~2014-11-24T06：33：11 + 00：00~GET / hot_search_words /？format = json＆amp; device_id = 9dcT9DnwXug7R4KHGZvC2PReGkg =＆amp; language_code = PT-BR HTTP / 1.1〜200〜1036〜 - 〜NativeHost〜0.009〜0.009〜。 107.77.80.86~ - 〜24 / Nov / 2014：06：33：12 + 0000~2014-11-24T06：33：12 + 00：00~GET / download_search / Linkin％20Park /？format = json＆amp; device_id = 8svpotKbUezqsRWIZrHER0IqEu8 =＆放大器; LANGUAGE_CODE = EN-US HTTP / 1.1〜200〜32708〜 - 〜NativeHost〜0.105〜0.105〜。 173.209.211.245~ - 〜24 / Nov / 2014：06：33：12 + 0000~2014-11-24T06：33：12 + 00：00~GET / download_search / tony％20toni％20tone％20just％20me％20and％ ？20you /格式= JSON和放大器; DEVICE_ID = wMvgYR5zUWlo8DuXdC6QjmMGAaY =安培; LANGUAGE_CODE = EN-US HTTP / 1.1〜200〜39〜 - 〜NativeHost〜0.122〜0.122〜
我使用fastcgi作为python wsgi服务器。过了一会儿，Web服务器正常。 我想知道为什么会这样，以及如何避免这次事故？