16 and和8核的最佳Apache & MySQL配置

Question

我的服务器出问题了。我有一个高峰，我的服务器负载非常高。

我有3台服务器，一台用于前端，一台用于数据库(mysql)，一台用于交付映像(这一台没有问题)

以下是我目前的配置和1500名访问者的平均负载：

服务器1(前端)：

load average: 143.08, 120.50, 66.99
CentOS 6.3
Apache/2.2.15
8 x Intel(R) Xeon(R) CPU E5645  @ 2.40GHz
16GB RAM

httpd.conf

PidFile run/httpd.pid
Timeout 60
KeepAlive Off
MaxKeepAliveRequests 1000
KeepAliveTimeout 15

<IfModule prefork.c>
  ServerLimit       520

  StartServers           16
  MinSpareServers         5
  MaxSpareServers        20
  MaxClients            500
  MaxRequestsPerChild  1000
</IfModule>

<IfModule worker.c>
  ServerLimit           520

  StartServers           16 
  MaxClients            500
  MinSpareThreads        25
  MaxSpareThreads        75 
  ThreadsPerChild        25
  MaxRequestsPerChild     0
</IfModule>

ExtendedStatus On
UseCanonicalName Off
HostnameLookups Off

ErrorLog logs/error_log
LogLevel warn

ServerSignature On


IndexOptions FancyIndexing VersionSort NameWidth=* HTMLTable Charset=UTF-8
BrowserMatch "Mozilla/2" nokeepalive
BrowserMatch "MSIE 4\.0b2;" nokeepalive downgrade-1.0 force-response-1.0
BrowserMatch "RealPlayer 4\.0" force-response-1.0
BrowserMatch "Java/1\.0" force-response-1.0
BrowserMatch "JDK/1\.0" force-response-1.0

BrowserMatch "Microsoft Data Access Internet Publishing Provider" redirect-carefully
BrowserMatch "MS FrontPage" redirect-carefully
BrowserMatch "^WebDrive" redirect-carefully
BrowserMatch "^WebDAVFS/1.[0123]" redirect-carefully
BrowserMatch "^gnome-vfs/1.0" redirect-carefully
BrowserMatch "^XML Spy" redirect-carefully
BrowserMatch "^Dreamweaver-WebDAV-SCM1" redirect-carefully

服务器2 (MySQL my.cnf)

load average: 12.84, 23.39, 22.85
CentOS 6.4
MYSQL 5.5.34
8 x Intel(R) Xeon(R) CPU E5645  @ 2.40GHz
16GB RAM

my.cnf

[mysqld]
port=3306
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0

max_connections = 2000

key_buffer = 384M
query_cache_type=1
query_cache_size=512M
query_cache_limit=4M

innodb_buffer_pool_size = 8G
slow_query_log=1
slow_query_log_file=log-slow-queries.log
thread_cache_size=8
table_cache=128k
tmp_table_size=256M
max_heap_table_size=256M

init_connect='SET collation_connection = latin1_swedish_ci'
init_connect='SET NAMES latin1'
character-set-server=latin1
collation-server=latin1_swedish_ci
skip-character-set-client-handshake

log-error=/var/log/mysqld.error.log

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

mysqltuner输出

-------- General Statistics --------------------------------------------------
[--] Skipped version check for MySQLTuner script
[OK] Currently running supported MySQL version 5.5.34-log
[OK] Operating on 64-bit architecture

-------- Storage Engine Statistics -------------------------------------------
[--] Status: +Archive -BDB -Federated +InnoDB -ISAM -NDBCluster 
[--] Data in InnoDB tables: 3G (Tables: 57)
[--] Data in PERFORMANCE_SCHEMA tables: 0B (Tables: 17)
[!!] Total fragmented tables: 57

-------- Security Recommendations  -------------------------------------------
[OK] All database users have passwords assigned

-------- Performance Metrics -------------------------------------------------
[--] Up for: 5h 11m 15s (4M q [241.514 qps], 537K conn, TX: 11B, RX: 2B)
[--] Reads / Writes: 87% / 13%
[--] Total buffers: 9.1G global + 2.8M per thread (2000 max threads)
[OK] Maximum possible memory usage: 14.5G (46% of installed RAM)
[OK] Slow queries: 1% (55K/4M)
[OK] Highest usage of available connections: 37% (756/2000)
[OK] Key buffer size / total MyISAM indexes: 384.0M/96.0K
[OK] Key buffer hit rate: 100.0% (46K cached / 0 reads)
[!!] Query cache efficiency: 0.0% (0 cached / 2M selects)
[OK] Query cache prunes per day: 0
[OK] Sorts requiring temporary tables: 0% (0 temp sorts / 480K sorts)
[OK] Temporary tables created on disk: 16% (112K on disk / 684K total)
[OK] Thread cache hit rate: 83% (87K created / 537K connections)
[OK] Table cache hit rate: 99% (2K open / 2K opened)
[OK] Open file limit used: 0% (19/264K)
[OK] Table locks acquired immediately: 100% (7M immediate / 7M locks)
[OK] InnoDB data size / buffer pool: 3.6G/8.0G

应用程序详细信息

PHP5.4 Symfony 1.2数据库大小: 6GB

你能帮帮我吗?

Answer 1

我在这里看到的主要问题是前端服务器的负载平均值很高。MySQL服务器可以做得更好，但也没有那么糟糕。Apache服务器经常成为瓶颈。在不知道应用程序正在做什么的情况下，很难解决这个问题。一般性建议可如下：

1. 在前端服务器上设置Munin，这将包括Apache的度量标准。有了这些信息，您将更容易调优Apache。Munin还将帮助您确定负载平均增加的频率和时间。
2. 分析Apache和应用程序日志。什么是最沉重和最频繁的请求？可能存在一些与应用程序相关的问题(比如使用PHP提供静态文件)。
3. 考虑切换到nginx/php而不是Apache。Apache是非常好的but服务器，但是nginx成为了许多不需要特定Apache特性的现代设置的标准。

考虑MySQL优化。您只有96.0K的MyISAM索引，而384.0M的密钥缓冲池。您可以安全地减少这个参数。您还可以使用Percona的pt查询摘要检查您的慢速查询，它非常方便。