管理员创建帖子时 CPU 和 RAM 已满

Question

我的 wordpress 网站每月有 300 万用户流量，在我们的管理员创建帖子/页面之前一切都很好。当我们的管理员创建帖子/页面时，我们的 CPU 和 RAM 使用率会增加到 100% 并且网站已关闭。我认为完成一些过程后，使用恢复正常状态，网站又恢复了。

我已经使用 Varnish 和 Wp- Rocket 来缓存内容。

这是我们的服务器配置 在 6 个 CPU 6GB RAM 上运行的 Wordpress（PHP 7.2 和 Apache/2.4.38）

我的 Apache 配置

<VirtualHost *:8080>
   <files xmlrpc.php>
      order allow,deny
      deny from all
    </files>
    ServerAdmin [email]
    ServerName [domain]
    ServerAlias [domain]
    DocumentRoot /var/www/html/[domain]/public_html
    SetEnvIf Remote_Addr "::1" dontlog
        SetEnvIf Remote_Addr "127.0.0.1" dontlog
        CustomLog /var/log/apache2/access.log combined env=!dontlog
    ErrorLog ${APACHE_LOG_DIR}/error.log
    CustomLog ${APACHE_LOG_DIR}/access.log combined

</VirtualHost>

#LoadModule ssl_module modules/mod_ssl.so
#Listen 443
<VirtualHost *:443>
    Protocols h2 http/1.1
    <files xmlrpc.php>
      order allow,deny
      deny from all
    </files>

    ServerAdmin [email]
    ServerName [domain]
    ServerAlias [domain]
    DocumentRoot /var/www/html/[domain]/public_html
    SSLEngine on
    SSLProtocol ALL -SSLv2 -SSLv3
    SSLHonorCipherOrder On
    SSLCipherSuite [chiper]
    SSLCertificateFile [cert]
    SSLCertificateKeyFile [cert]
    SSLCertificateChainFile [cert]
</VirtualHost>
<Directory /var/www/html/[domain]/public_html>
                Options Indexes FollowSymLinks MultiViews
                AllowOverride All
                Order allow,deny
                Require all granted
</Directory>

Apache 配置

Mutex file:${APACHE_LOCK_DIR} default
PidFile ${APACHE_PID_FILE}
Timeout 240
KeepAlive On
MaxKeepAliveRequests 500
KeepAliveTimeout 6

# These need to be set in /etc/apache2/envvars
User ${APACHE_RUN_USER}
Group ${APACHE_RUN_GROUP}

HostnameLookups Off
ErrorLog ${APACHE_LOG_DIR}/error.log

LogLevel warn

# Include module configuration:
IncludeOptional mods-enabled/*.load
IncludeOptional mods-enabled/*.conf

# Include list of ports to listen on
Include ports.conf

<Directory />
    Options FollowSymLinks
    AllowOverride None
    Require all denied
</Directory>

<Directory /usr/share>
    AllowOverride None
    Require all granted
</Directory>

<Directory /var/www/>
    Options Indexes FollowSymLinks
    AllowOverride None
    Require all granted
</Directory>

AccessFileName .htaccess

<FilesMatch "^\.ht">
    Require all denied
</FilesMatch>

LogFormat "%v:%p %h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" vhost_combined
LogFormat "%h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" combined
LogFormat "%h %l %u %t \"%r\" %>s %O" common
LogFormat "%{Referer}i -> %U" referer
LogFormat "%{User-agent}i" agent

# Include generic snippets of statements
IncludeOptional conf-enabled/*.conf

# Include the virtual host configurations:
IncludeOptional sites-enabled/*.conf

MPM Prefork 配置：

# prefork MPM
# StartServers: number of server processes to start
# MinSpareServers: minimum number of server processes which are kept spare
# MaxSpareServers: maximum number of server processes which are kept spare
# MaxRequestWorkers: maximum number of server processes allowed to start
# MaxConnectionsPerChild: maximum number of requests a server process serves

<IfModule mpm_prefork_module>
        StartServers            5
        MinSpareServers         5
        MaxSpareServers         10
        MaxRequestWorkers       500
        MaxConnectionsPerChild  100
        ServerLimit 1024
</IfModule>

第二次更新 我将数据库服务器增加到 6 个 CPU 和 10GB RAM。仍然有这个问题这是我的 my.cnf 配置：

#
# * Fine Tuning
#
max_connections     = 300
connect_timeout     = 200
wait_timeout        = 300
max_allowed_packet  = 16M
thread_cache_size       = 50
sort_buffer_size    = 2M
bulk_insert_buffer_size = 160M
tmp_table_size      = 256M
max_heap_table_size = 256M
thread_stack            = 50K
#
# * MyISAM
#
# This replaces the startup script and checks MyISAM tables if needed
# the first time they are touched. On error, make copy and try a repair.
myisam_recover_options = BACKUP
key_buffer_size     = 16M
#open-files-limit   = 2000
table_open_cache    = 400
myisam_sort_buffer_size = 512M
concurrent_insert   = 2
read_buffer_size    = 512K
read_rnd_buffer_size    = 192K
#
# * Query Cache Configuration
#
# Cache only tiny result sets, so we can fit more in the query cache.
query_cache_limit       = 128K
#query_cache_size       = 50M
query_cache_size = 0
# for more write intensive setups, set to DEMAND or OFF
query_cache_type        = 0
#
# * Logging and Replication
#
# Both location gets rotated by the cronjob.
# Be aware that this log type is a performance killer.
# As of 5.1 you can enable the log at runtime!
#general_log_file        = /var/log/mysql/mysql.log
#general_log             = 1
#
# Error logging goes to syslog due to /etc/mysql/conf.d/mysqld_safe_syslog.cnf.
#
# we do want to know about network errors and such
log_warnings        = 2
#
# Enable the slow query log to see queries with especially long duration
#slow_query_log[={0|1}]
slow_query_log = 1
slow_query_log_file = /var/log/mysql/mariadb-slow.log
long_query_time = 1
log_queries_not_using_indexes
#log_slow_rate_limit    = 1000
log_slow_verbosity  = query_plan

#log-queries-not-using-indexes
#log_slow_admin_statements
#
# The following can be used as easy to replay backup logs or for replication.
# note: if you are setting up a replication slave, see README.Debian about
#       other settings you may need to change.
#server-id      = 1
#report_host        = master1
#auto_increment_increment = 2
#auto_increment_offset  = 1
log_bin         = /var/log/mysql/mariadb-bin
log_bin_index       = /var/log/mysql/mariadb-bin.index
# not fab for performance, but safer
#sync_binlog        = 1
expire_logs_days    = 10
max_binlog_size         = 100M
# slaves
#relay_log      = /var/log/mysql/relay-bin
#relay_log_index    = /var/log/mysql/relay-bin.index
#relay_log_info_file    = /var/log/mysql/relay-bin.info
#log_slave_updates
#read_only
#
# If applications support it, this stricter sql_mode prevents some
# mistakes like inserting invalid dates etc.
#sql_mode       = NO_ENGINE_SUBSTITUTION,TRADITIONAL
#
# * InnoDB
#
# InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/.
# Read the manual for more InnoDB related options. There are many!
default_storage_engine  = InnoDB
# you can't just change log file size, requires special procedure
#innodb_log_file_size   = 50M
innodb_buffer_pool_instances = 7
innodb_buffer_pool_size = 7G
innodb_log_file_size    = 512M
innodb_log_buffer_size  = 16M
innodb_file_per_table   = 1
innodb_open_files   = 400
innodb_io_capacity  = 1000
innodb_flush_log_at_trx_commit = 0
innodb_flush_method = O_DIRECT
innodb_stats_on_metadata = 0
innodb_read_io_threads = 64
innodb_write_io_threads = 64
innodb_lru_scan_depth = 100
#
# * Security Features
#
# Read the manual, too, if you want chroot!
# chroot = /var/lib/mysql/
#
# For generating SSL certificates I recommend the OpenSSL GUI "tinyca".
#
# ssl-ca=/etc/mysql/cacert.pem
# ssl-cert=/etc/mysql/server-cert.pem
# ssl-key=/etc/mysql/server-key.pem

#
# * Galera-related settings
#
[galera]
# Mandatory settings
#wsrep_on=ON
#wsrep_provider=
#wsrep_cluster_address=
#binlog_format=row
#default_storage_engine=InnoDB
#innodb_autoinc_lock_mode=2
#
# Allow server to accept connections on all interfaces.
#
#bind-address=0.0.0.0
#
# Optional setting
#wsrep_slave_threads=1
#innodb_flush_log_at_trx_commit=0

[mysqldump]
quick
quote-names
max_allowed_packet  = 512M

[mysql]
#no-auto-rehash # faster start of mysql but no tab completion

[isamchk]
key_buffer      = 2G

#
# * IMPORTANT: Additional settings that can override those from this file!
#   The files must end with '.cnf', otherwise they'll be ignored.
#
!includedir /etc/mysql/conf.d/

我用的是mysqltuner，结果是这样的

 >>  MySQLTuner 1.7.4 - Major Hayden <major@mhtx.net>
 >>  Bug reports, feature requests, and downloads at http://mysqltuner.com/
 >>  Run with '--help' for additional options and output filtering

[--] Skipped version check for MySQLTuner script
[OK] Logged in using credentials from debian maintenance account.
[OK] Currently running supported MySQL version 10.4.6-MariaDB-1:10.4.6+maria~bionic-log
[OK] Operating on 64-bit architecture

-------- Log file Recommendations ------------------------------------------------------------------
[--] Log file: /var/lib/mysql/web-db-instance-new.err(0B)
[!!] Log file /var/lib/mysql/web-db-instance-new.err doesn't exist
[!!] Log file /var/lib/mysql/web-db-instance-new.err isn't readable.

-------- Storage Engine Statistics -----------------------------------------------------------------
[--] Status: +Aria +CSV +InnoDB +MEMORY +MRG_MyISAM +MyISAM +PERFORMANCE_SCHEMA +SEQUENCE
[--] Data in InnoDB tables: 1G (Tables: 360)
[--] Data in MyISAM tables: 1G (Tables: 269)
[OK] Total fragmented tables: 0

-------- Security Recommendations ------------------------------------------------------------------
[OK] There are no anonymous accounts for any database users
[OK] All database users have passwords assigned
[!!] User 'finansialku@%' hasn't specific host restriction.
[!!] There is no basic password file list!

-------- CVE Security Recommendations --------------------------------------------------------------
[--] Skipped due to --cvefile option undefined

-------- Performance Metrics -----------------------------------------------------------------------
[--] Up for: 49s (43K q [887.163 qps], 749 conn, TX: 3G, RX: 16M)
[--] Reads / Writes: 97% / 3%
[--] Binary logging is enabled (GTID MODE: OFF)
[--] Physical Memory     : 9.8G
[--] Max MySQL memory    : 8.3G
[--] Other process memory: 152.7M
[--] Total buffers: 7.4G global + 3.1M per thread (300 max threads)
[--] P_S Max memory usage: 0B
[--] Galera GCache Max memory usage: 0B
[OK] Maximum reached memory usage: 7.8G (80.01% of installed RAM)
[!!] Maximum possible memory usage: 8.3G (85.09% of installed RAM)
[OK] Overall possible memory usage with other process is compatible with memory available
[OK] Slow queries: 2% (1K/43K)
[OK] Highest usage of available connections: 44% (134/300)
[OK] Aborted connections: 0.00%  (0/749)
[OK] Query cache is disabled by default due to mutex contention on multiprocessor machines.
[OK] Sorts requiring temporary tables: 0% (1 temp sorts / 9K sorts)
[!!] Joins performed without indexes: 2
[!!] Temporary tables created on disk: 71% (1K on disk / 2K total)
[OK] Thread cache hit rate: 82% (134 created / 749 connections)
[OK] Table cache hit rate: 79% (400 open / 506 opened)
[OK] Open file limit used: 39% (587/1K)
[!!] Table locks acquired immediately: 69%
[OK] Binlog cache memory access: 100.00% (23 Memory / 23 Total)

-------- Performance schema ------------------------------------------------------------------------
[--] Performance schema is disabled.
[--] Memory used by P_S: 0B
[--] Sys schema isn't installed.

-------- ThreadPool Metrics ------------------------------------------------------------------------
[--] ThreadPool stat is enabled.
[--] Thread Pool Size: 6 thread(s).
[--] Using default value is good enough for your version (10.4.6-MariaDB-1:10.4.6+maria~bionic-log)

-------- MyISAM Metrics ----------------------------------------------------------------------------
[OK] Key buffer used: 100.0% (16M used / 16M cache)
[OK] Key buffer size / total MyISAM indexes: 16.0M/135.8M
[OK] Read Key buffer hit rate: 98.8% (5M cached / 62K reads)
[!!] Write Key buffer hit rate: 83.5% (1K cached / 1K writes)

-------- InnoDB Metrics ----------------------------------------------------------------------------
[--] InnoDB is enabled.
[--] InnoDB Thread Concurrency: 0
[OK] InnoDB File per table is activated
[OK] InnoDB buffer pool / data size: 7.0G/2.0G
[!!] Ratio InnoDB log file size / InnoDB Buffer pool size (14.2857142857143 %): 512.0M * 2/7.0G should be equal 25%
[OK] InnoDB buffer pool instances: 7
[--] Number of InnoDB Buffer Pool Chunk : 56 for 7 Buffer Pool Instance(s)
[OK] Innodb_buffer_pool_size aligned with Innodb_buffer_pool_chunk_size & Innodb_buffer_pool_instances
[OK] InnoDB Read buffer efficiency: 95.68% (1415595 hits/ 1479512 total)
[!!] InnoDB Write Log efficiency: 15% (6 hits/ 40 total)
[OK] InnoDB log waits: 0.00% (0 waits / 34 writes)

-------- AriaDB Metrics ----------------------------------------------------------------------------
[--] AriaDB is enabled.
[OK] Aria pagecache size / total Aria indexes: 128.0M/296.0K
[OK] Aria pagecache hit rate: 99.4% (235K cached / 1K reads)

-------- TokuDB Metrics ----------------------------------------------------------------------------
[--] TokuDB is disabled.

-------- XtraDB Metrics ----------------------------------------------------------------------------
[--] XtraDB is disabled.

-------- RocksDB Metrics ---------------------------------------------------------------------------
[--] RocksDB is disabled.

-------- Spider Metrics ----------------------------------------------------------------------------
[--] Spider is disabled.

-------- Connect Metrics ---------------------------------------------------------------------------
[--] Connect is disabled.

-------- Galera Metrics ----------------------------------------------------------------------------
[--] Galera is disabled.

-------- Replication Metrics -----------------------------------------------------------------------
[--] Galera Synchronous replication: NO
[--] No replication slave(s) for this server.
[--] This is a standalone server.

-------- Recommendations ---------------------------------------------------------------------------
General recommendations:
    Restrict Host for user@% to user@SpecificDNSorIp
    MySQL started within last 24 hours - recommendations may be inaccurate
    Reduce your overall MySQL memory footprint for system stability
    Adjust your join queries to always utilize indexes
    Temporary table size is already large - reduce result set size
    Reduce your SELECT DISTINCT queries without LIMIT clauses
    Optimize queries and/or use InnoDB to reduce lock wait
    Performance should be activated for better diagnostics
    Consider installing Sys schema from https://github.com/mysql/mysql-sys
    Read this before changing innodb_log_file_size and/or innodb_log_files_in_group
Variables to adjust:
    join_buffer_size (> 256.0K, or always use indexes with joins)
    performance_schema = ON enable PFS
    innodb_log_file_size should be (=896M) if possible, so InnoDB total log files size equals to 25% of buffer pool size.

我需要先解决什么问题？

Answer 1

当配置设置太高时，RAM 会填满，然后 Swap 会填满。这极大地降低了 MySQL 的速度。解决方法是撤消设置。

但首先，表是 MyISAM 吗？还是 InnoDB？

以下是看起来特别危险的值：

max_allowed_packet  = 512M    -- go back to 16M
thread_cache_size       = 256K  -- This is threads! not bytes!  change to 50
tmp_table_size      = 1024M   -- change to 1% of RAM
max_heap_table_size = 1024M   -- change to 1% of RAM

myisam_sort_buffer_size = 512M   --> 8M
read_buffer_size    = 2M      --> 128K
read_rnd_buffer_size    = 1M  --> 256K

query_cache_limit       = 256K
query_cache_size        = 250M  -- Drop to 50M; 250M slows things down

# Enable the slow query log to see queries with especially long duration
#slow_query_log[={0|1}]    -- yes, enable it
long_query_time = 1
log_queries_not_using_indexes  -- unnecessarily clutters the slowlog

innodb_io_capacity  = 1000   -- Do you have SSD?

至于这些：

key_buffer_size     = 128M    -->
innodb_buffer_pool_size = 4G  -->

如果主要使用 MyISAM：

key_buffer_size     = 128M    -->  OK
innodb_buffer_pool_size = 4G  -->  16M

如果主要使用 InnoDB：

key_buffer_size     = 128M    -->  20M
innodb_buffer_pool_size = 4G  -->  3500M

Answer 2

Rate Per Second=RPS - 为您的 my.cnf [mysqld] 部分考虑的建议

sort_buffer_size=2M  # from 40M for a more reasonable per connection requirement
read_rnd_buffer_size=192K  # from 1M to reduce handler_read_rnd_next RPS
read_buffer_size=512K  # from 2M to increase handler_read_next RPS
innodb_lru_scan_depth=100  # from 1024 to reduce CPU cycles used for function

免责声明：我是我的个人资料中提到的网站的内容作者，用于提高性能的实用脚本网络配置文件和其他建议，请参阅我们的联系信息。