要检查挂灯服务器的日志是什么？

Question

我在运行Centos 5.7。我运行Apache，MySQL，PHP，Courier，Qmail和Plesk控制面板，在一个典型的网络主机服务器设置。它常被挂起来。

我不得不通过管理面板重新启动服务器，因为没有Plesk或SSH访问.如何防止这种情况再次发生？

处理器: AMD (Tm) II X4 RAM: 8GB

我注意到Apache日志中有一些错误：

# tail -20 /var/log/httpd/error_log

[Mon Sep 03 06:12:33 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/web
[Mon Sep 03 06:12:34 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/php-my-admin
[Mon Sep 03 06:12:34 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/websql
[Mon Sep 03 06:12:35 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/phpmyadmin
[Mon Sep 03 06:12:36 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin
[Mon Sep 03 06:12:36 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2
[Mon Sep 03 06:12:37 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/php-my-admin
[Mon Sep 03 06:12:38 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2.2.3
[Mon Sep 03 06:12:38 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2.2.6
[Mon Sep 03 06:12:39 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2.5.1
[Mon Sep 03 06:12:39 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2.5.4
[Mon Sep 03 06:12:40 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2.5.5-rc1
[Mon Sep 03 06:12:41 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2.5.5-rc2
[Mon Sep 03 06:12:41 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2.5.5
[Mon Sep 03 06:12:42 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2.5.5-pl1
[Mon Sep 03 06:12:43 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2.5.6-rc1
[Mon Sep 03 06:12:43 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2.5.6-rc2
[Mon Sep 03 06:12:44 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2.5.6
[Mon Sep 03 06:12:45 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2.5.7
[Mon Sep 03 06:12:45 2012] [error] [client 202.29.34.28] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin-2.5.7-pl1

还注意到一些mysql慢速查询：

# Query_time: 23.734215  Lock_time: 0.000111 Rows_sent: 1  Rows_examined: 2501281
use yasooyam_yasoodb;
SET timestamp=1346149823;
SELECT COUNT(user_history_product.ID) FROM user_history_product WHERE user_history_product.PRODUCT_ID=915;

# Query_time: 293.916966  Lock_time: 1.163037 Rows_sent: 1  Rows_examined: 2501280
SET timestamp=1346149823;
SELECT COUNT(user_history_product.ID) FROM user_history_product WHERE user_history_product.PRODUCT_ID=172;

# Query_time: 61.295134  Lock_time: 0.000345 Rows_sent: 331  Rows_examined: 331
use pumexinf_mdb;
SET timestamp=1346149825;
show tables;

# Query_time: 16.869923  Lock_time: 2.281526 Rows_sent: 1889  Rows_examined: 9330
use yasooyam_yasoodb;
SET timestamp=1346586973;
SELECT user_items.ID, user_items.TYPE, user_items.USER_ID, user_items.SHOW_IN, user_items.CATEGORY, user_items.SUB_CATEGORY, user_items.COUNTRY, user_items.LANGUAGE, user_items.TITLE, user_items.START_TIME, user_items.END_TIME, user_items.DATE, user_items.DESCRIPTION, user_items.ATTACH, user_items.IMAGE, user_items.IMAGE_AUTHOR, user_items.IMAGE_SOURCE, user_items.VIDEO_URL, user_items.THUMB, user_items.AUTHOR, user_items.SOURCE, user_items.CREATE_DATE, user_items.UPDATE_DATE, user_items.STATUS FROM user_items WHERE user_items.TYPE=9 AND user_items.STATUS=1;

Answer 1

根据apache2日志，挂起肯定不是(文件找不到)致命错误的结果。

这取决于您在my.cnf中为mysqld预留了多少内存。

你需要更多地调查这件事的原因。

很少有值得注意的事情需要调查：

• 服务器挂起(拒绝服务)可能是两件事的结果，过处理器负载或导致拒绝服务的应用程序。
• 检查系统日志而不是应用程序日志以获得更多的洞察力。
• 通过安装deflateDOS和SELinux来采取预防措施，检查它们的日志
• 记住，像top和netstat这样的命令非常有用。

Answer 2

尝试安装像穆宁这样的监控软件。使用munin插件，您可以监控许多事情随着时间的推移。例如，您可以在服务器挂起之前看到Apache请求中的尖峰，或者磁盘I/O或mysql连接。有了这样一个软件，就更容易找到源文件。