我们有一个具有 32GB 内存的 2003 集群。
它托管两个 SQL 2005 数据库实例、一个报告实例并全天运行 SSIS 包。
主实例设置为 22GB 内存，第二个用于 SharePoint，已设置为 4GB 并限制为 2 个处理器 - 大家对 sharepoint 非常怀疑，所以它被锁定了。
Reporting Services 的应用程序池限制为 6GB - 这可能会减少。报告服务很快就会转移到它自己的服务器上，所以我们将摆脱这种情况。
通过以这种方式设置内存，我们希望不会让应用程序不断地争夺内存。
我们现在需要为一些将从 2005 实例移出的 Web 应用程序设置 2008 实例。
我们在服务器上没有看到太多的分页——它通常以 0 到 8 页/秒的速度运行，并且到处跳到几百页。
两个实例的总/目标 SQL 内存值相同。我希望看到主实例的目标内存值较低，我会将内存减少到该级别以为新实例腾出空间。过去我看到目标内存比总数低几百兆字节。
你们会建议做什么来为这个新实例腾出空间同时让其他实例满意？也许与主实例一起动态？慢慢减少主实例的最大值，直到分页或其他一些计数器上升？
MySQL 不是我的菜，但我需要微调我们的一台服务器。
以下是要求/规格：
按照现在的配置，我们的 MySQL 服务器慢慢开始消耗所有可用内存（我们使用 collectd，这是一个图表）。在某个时候（几天/几周后），它停止执行查询（今晚停止了 2 个小时，我不得不重新启动 MySQL 服务器：参见第二张图片）：
（抱歉，新用户无法发布图片，并且只有 1 个超链接：/）
每周：http: //i27.tinypic.com/6ticyv.jpg
今天：i31.tinypic.com/ir53yg.png
这是我们当前的 my.cnf
#
# The MySQL database server configuration file.
#
# This will be passed to all mysql clients
# It has been reported that passwords should be enclosed with ticks/quotes
# escpecially if they contain "#" chars...
# Remember to edit /etc/mysql/debian.cnf when changing the socket location.
[client]
port = 3306
socket = /var/run/mysqld/mysqld.sock
# Here is entries for some specific programs
# The following values assume you have at least 32M ram
# This was formally known as [safe_mysqld]. Both versions are currently parsed.
[mysqld_safe]
socket = /var/run/mysqld/mysqld.sock
nice = 0
[mysqld]
#
# * Basic Settings
#
#
# * IMPORTANT
# If you make changes to these settings and your system uses apparmor, you may
# also need to also adjust /etc/apparmor.d/usr.sbin.mysqld.
#
user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
language = /usr/share/mysql/english
skip-external-locking
#
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
# yann changed this on a friday balbla
#bind-address = 127.0.0.1
bind-address = 0.0.0.0
#
# * Fine Tuning
#
key_buffer = 16M
max_allowed_packet = 16M
thread_stack = 128K
thread_cache_size = 8
# This replaces the startup script and checks MyISAM tables if needed
# the first time they are touched
myisam-recover = BACKUP
max_connections = 2000
#table_cache = 64
#thread_concurrency = 10
#
# * Query Cache Configuration
#
query_cache_limit = 1M
query_cache_size = 16M
#
# * Logging and Replication
#
# Both location gets rotated by the cronjob.
# Be aware that this log type is a performance killer.
# log = /var/log/mysql/mysql.log
#
# Error logging goes to syslog. This is a Debian improvement :)
#
# Here you can see queries with especially long duration
log_slow_queries = /var/log/mysql/mysql-slow.log
long_query_time = 3
log-queries-not-using-indexes
#
# 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
#log_bin = /var/log/mysql/mysql-bin.log
expire_logs_days = 10
max_binlog_size = 100M
#binlog_do_db = include_database_name
#binlog_ignore_db = include_database_name
#
# * BerkeleyDB
#
# Using BerkeleyDB is now discouraged as its support will cease in 5.1.12.
skip-bdb
#
# * 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!
# You might want to disable InnoDB to shrink the mysqld process by circa 100MB.
#skip-innodb
# Fine tunig added by JG on 06/03 based on http://www.mysqlperformanceblog.com/2007/11/01/innodb-performance-optimization-basics/
innodb_buffer_pool_size = 1G
#innodb_log_file_size = 256M
innodb_log_buffer_size = 4M
innodb_flush_log_at_trx_commit = 2
innodb_thread_concurrency = 8
innodb_flush_method = O_DIRECT
innodb_file_per_table
transaction-isolation = READ-COMMITTED
innodb_table_locks = 0
#
# * Federated
#
# The FEDERATED storage engine is disabled since 5.0.67 by default in the .cnf files
# shipped with MySQL distributions (my-huge.cnf, my-medium.cnf, and so forth).
#
skip-federated
#
# * 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
[mysqldump]
quick
quote-names
max_allowed_packet = 16M
[mysql]
#no-auto-rehash # faster start of mysql but no tab completition
[isamchk]
key_buffer = 16M
#
# * NDB Cluster
#
# See /usr/share/doc/mysql-server-*/README.Debian for more information.
#
# The following configuration is read by the NDB Data Nodes (ndbd processes)
# not from the NDB Management Nodes (ndb_mgmd processes).
#
# [MYSQL_CLUSTER]
# ndb-connectstring=127.0.0.1
#
# * 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/
这是慢查询的转储：
$ mysqldumpslow /var/log/mysql/mysql-slow.log
Reading mysql slow query log from /var/log/mysql/mysql-slow.log
Count: 5 Time=3689348814741910528.00s (-1s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158]
SET insert_id=N;
INSERT IGNORE INTO `feeds` (`url`) VALUES ('S')
Count: 41 Time=1349761761490942720.00s (-1s) Lock=0.12s (5s) Rows=253.0 (10373), superfeeder[superfeeder]@localhost
SHOW GLOBAL STATUS
Count: 25 Time=737869762948382080.00s (-1s) Lock=0.00s (0s) Rows=18.1 (452), superfeeder[superfeeder]@[172.21.1.158]
SELECT `feeds`.* FROM `feeds` WHERE (`fetch_session_id` = 'S')
Count: 12952 Time=1424239042133230.25s (-1s) Lock=0.00s (1s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158]
SET insert_id=N;
INSERT IGNORE INTO `entries` (`chunks`, `time`, `feed_id`, `unique_id`, `link`, `chunk`) VALUES ('S', 'S', N, 'S', 'S', 'S')
Count: 29 Time=656.55s (19040s) Lock=5.28s (153s) Rows=0.8 (23), superfeeder[superfeeder]@[172.21.1.175]
select salt,crypted_password from users where login='S'
Count: 39 Time=505.23s (19704s) Lock=2.41s (94s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184]
DELETE FROM `feeds` WHERE (url LIKE 'S')
Count: 2275 Time=502.50s (1143184s) Lock=3.48s (7922s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158]
UPDATE `feeds` SET `next_fetch` = 'S', `fetch_session_id` = 'S' WHERE (`next_fetch` < 'S') LIMIT N
Count: 1 Time=443.00s (443s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184]
UPDATE `feeds` SET `next_fetch` = 'S' WHERE (`feeds`.`url` IN (NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL))
Count: 14 Time=289.43s (4052s) Lock=0.71s (10s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184]
UPDATE `feeds` SET `next_fetch` = 'S' WHERE (`feeds`.`url` IN ('S','S'))
Count: 2 Time=256.00s (512s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184]
UPDATE `feeds` SET `next_fetch` = 'S' WHERE (`feeds`.`url` IN (NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL))
Count: 1 Time=237.00s (237s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184]
UPDATE `feeds` SET `next_fetch` = 'S' WHERE (`feeds`.`url` IN ('S'))
Count: 24 Time=191.58s (4598s) Lock=1.12s (27s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184]
UPDATE `feeds` SET `next_fetch` = 'S' WHERE (`feeds`.`id` = 'S')
Count: 5 Time=144.20s (721s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184]
UPDATE `feeds` SET `next_fetch` = 'S' WHERE (`feeds`.`url` IN (NULL,NULL,NULL))
Count: 1 Time=101.00s (101s) Lock=1.00s (1s) Rows=1.0 (1), superfeeder[superfeeder]@[172.21.1.158]
SELECT * FROM `users` WHERE (`login` = 'S') LIMIT N
Count: 79 Time=35.51s (2805s) Lock=2.52s (199s) Rows=0.2 (12), superfeeder[superfeeder]@[172.21.1.184]
SELECT `feeds`.id FROM `feeds` WHERE (`feeds`.`url` = BINARY 'S' AND `feeds`.id <> N) LIMIT N
Count: 1 Time=28.00s (28s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184]
UPDATE `feeds` SET `last_maintenance_at` = 'S', `updated_at` = 'S' WHERE `id` = N
Count: 51 Time=23.51s (1199s) Lock=0.12s (6s) Rows=19.2 (981), superfeeder[superfeeder]@2hosts
SELECT version FROM schema_migrations
Count: 5 Time=20.60s (103s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184]
BEGIN
Count: 65 Time=15.86s (1031s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158]
UPDATE `feeds` SET `last_error_message` = 'S', `period` = 'S', `last_sup_update_id` = NULL, `updated_at` = 'S', `modified` = 'S', `fetch_session_id` = 'S', `streamed` = 'S', `last_parse` = 'S', `etag` = 'S', `last_entry_time` = 'S', `min_period` = 'S', `url` = 'S', `id` = 'S', `feed_type` = NULL, `sup_id` = NULL, `sup_url_id` = NULL, `next_fetch` = 'S', `hashed_content` = 'S', `last_maintenance_at` = 'S', `last_ping` = NULL, `last_http_code` = 'S', `active` = 'S', `last_fetch` = 'S', `created_at` = 'S', `max_period` = 'S' WHERE (`id` = N)
Count: 23 Time=11.52s (265s) Lock=0.00s (0s) Rows=231.0 (5313), superfeeder[superfeeder]@2hosts
#
Count: 132 Time=10.53s (1390s) Lock=0.02s (2s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158]
UPDATE `feeds` SET `last_error_message` = 'S', `period` = 'S', `last_sup_update_id` = NULL, `updated_at` = 'S', `modified` = 'S', `fetch_session_id` = 'S', `streamed` = 'S', `last_parse` = 'S', `etag` = 'S', `last_entry_time` = 'S', `min_period` = 'S', `url` = 'S', `id` = 'S', `feed_type` = NULL, `sup_id` = NULL, `sup_url_id` = NULL, `next_fetch` = 'S', `hashed_content` = 'S', `last_maintenance_at` = 'S', `last_ping` = NULL, `last_http_code` = 'S', `active` = 'S', `last_fetch` = 'S', `created_at` = NULL, `max_period` = 'S' WHERE (`id` = N)
Count: 62 Time=9.81s (608s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.184]
ROLLBACK
Count: 151 Time=8.94s (1350s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@2hosts
DELETE FROM `entries` WHERE (`time` < 'S')
Count: 25 Time=8.76s (219s) Lock=0.00s (0s) Rows=1.0 (24), superfeeder[superfeeder]@[172.21.1.158]
SELECT * FROM `feeds` WHERE (`url` = 'S') LIMIT N
Count: 2 Time=8.50s (17s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158]
set SQL_AUTO_IS_NULL=N
Count: 8802 Time=8.44s (74319s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158]
INSERT IGNORE INTO `entries` (`chunks`, `time`, `feed_id`, `unique_id`, `link`, `chunk`) VALUES ('S', 'S', N, 'S', 'S', 'S')
Count: 1 Time=8.00s (8s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158]
INSERT IGNORE INTO `subscriptions` (`user_id`, `feed_id`) VALUES (N, N)
Count: 38 Time=7.92s (301s) Lock=0.00s (0s) Rows=1.0 (38), superfeeder[superfeeder]@[172.21.1.184]
SELECT count(DISTINCT `users`.id) AS count_users_id FROM `users` INNER JOIN `subscriptions` ON `users`.id = `subscriptions`.user_id WHERE ((`subscriptions`.feed_id = N))
Count: 9 Time=7.67s (69s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158]
INSERT IGNORE INTO `feeds` (`url`) VALUES ('S')
Count: 244 Time=7.20s (1756s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158]
UPDATE `feeds` SET `last_error_message` = 'S', `period` = N, `last_sup_update_id` = NULL, `updated_at` = 'S', `modified` = 'S', `fetch_session_id` = 'S', `streamed` = 'S', `last_parse` = 'S', `etag` = 'S', `last_entry_time` = 'S', `min_period` = 'S', `url` = 'S', `id` = 'S', `feed_type` = NULL, `sup_id` = NULL, `sup_url_id` = NULL, `next_fetch` = 'S', `hashed_content` = 'S', `last_maintenance_at` = 'S', `last_ping` = NULL, `last_http_code` = N, `active` = 'S', `last_fetch` = 'S', `created_at` = 'S', `max_period` = 'S' WHERE (`id` = N)
Count: 336 Time=6.85s (2301s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158]
UPDATE `feeds` SET `last_error_message` = 'S', `period` = N, `last_sup_update_id` = NULL, `updated_at` = 'S', `modified` = 'S', `fetch_session_id` = 'S', `streamed` = 'S', `last_parse` = 'S', `etag` = 'S', `last_entry_time` = 'S', `min_period` = 'S', `url` = 'S', `id` = 'S', `feed_type` = NULL, `sup_id` = NULL, `sup_url_id` = NULL, `next_fetch` = 'S', `hashed_content` = 'S', `last_maintenance_at` = 'S', `last_ping` = NULL, `last_http_code` = N, `active` = 'S', `last_fetch` = 'S', `created_at` = NULL, `max_period` = 'S' WHERE (`id` = N)
Count: 16 Time=6.38s (102s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158]
UPDATE `feeds` SET `last_error_message` = 'S', `period` = N, `last_sup_update_id` = NULL, `updated_at` = NULL, `modified` = 'S', `fetch_session_id` = 'S', `streamed` = 'S', `last_parse` = 'S', `etag` = 'S', `last_entry_time` = 'S', `min_period` = 'S', `url` = 'S', `id` = 'S', `feed_type` = NULL, `sup_id` = NULL, `sup_url_id` = NULL, `next_fetch` = 'S', `hashed_content` = 'S', `last_maintenance_at` = 'S', `last_ping` = NULL, `last_http_code` = N, `active` = 'S', `last_fetch` = 'S', `created_at` = NULL, `max_period` = 'S' WHERE (`id` = N)
Count: 122 Time=5.91s (721s) Lock=0.00s (0s) Rows=1.0 (119), superfeeder[superfeeder]@[172.21.1.158]
SELECT DISTINCT `users`.* FROM `users` INNER JOIN `subscriptions` ON (`subscriptions`.`user_id` = `users`.`id`) WHERE (`subscriptions`.`feed_id` = N)
Count: 299 Time=5.78s (1727s) Lock=0.00s (0s) Rows=1.0 (299), superfeeder[superfeeder]@[172.21.1.158]
SELECT * FROM `feeds` WHERE (`id` = 'S')
Count: 21 Time=5.48s (115s) Lock=0.00s (0s) Rows=1.0 (21), superfeeder[superfeeder]@[172.21.1.158]
SELECT * FROM `subscriptions` WHERE ((`user_id` = N) AND (`feed_id` = N)) LIMIT N
Count: 27 Time=5.37s (145s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158]
UPDATE `feeds` SET `last_error_message` = 'S', `period` = 'S', `last_sup_update_id` = NULL, `updated_at` = NULL, `modified` = 'S', `fetch_session_id` = 'S', `streamed` = 'S', `last_parse` = 'S', `etag` = 'S', `last_entry_time` = 'S', `min_period` = 'S', `url` = 'S', `id` = 'S', `feed_type` = NULL, `sup_id` = NULL, `sup_url_id` = NULL, `next_fetch` = 'S', `hashed_content` = 'S', `last_maintenance_at` = 'S', `last_ping` = NULL, `last_http_code` = 'S', `active` = 'S', `last_fetch` = 'S', `created_at` = NULL, `max_period` = 'S' WHERE (`id` = N)
Count: 9 Time=4.33s (39s) Lock=0.00s (0s) Rows=0.0 (0), superfeeder[superfeeder]@[172.21.1.158]
UPDATE `feeds` SET `last_error_message` = 'S', `period` = 'S', `last_sup_update_id` = NULL, `updated_at` = NULL, `modified` = 'S', `fetch_session_id` = 'S', `streamed` = 'S', `last_parse` = 'S', `etag` = 'S', `last_entry_time` = 'S', `min_period` = 'S', `url` = 'S', `id` = 'S', `feed_type` = NULL, `sup_id` = NULL, `sup_url_id` = NULL, `next_fetch` = 'S', `hashed_content` = 'S', `last_maintenance_at` = 'S', `last_ping` = NULL, `last_http_code` = NULL, `active` = 'S', `last_fetch` = 'S', `created_at` = NULL, `max_period` = 'S' WHERE (`id` = N)
Count: 1 Time=4.00s (4s) Lock=0.00s (0s) Rows=1.0 (1), superfeeder[superfeeder]@[172.21.1.175]
select id from users where login='S'
Count: 1 Time=3.00s (3s) Lock=0.00s (0s) Rows=22.0 (22), debian-sys-maint[debian-sys-maint]@localhost
select concat("S",
TABLE_SCHEMA, "S", TABLE_NAME, "S")
from information_schema.TABLES where ENGINE="S"
Count: 1056 Time=0.11s (111s) Lock=0.00s (0s) Rows=126.9 (133998), superfeeder[superfeeder]@[172.21.1.184]
SELECT * FROM `feeds` WHERE (last_maintenance_at < 'S')
Count: 1049 Time=0.00s (1s) Lock=0.00s (0s) Rows=3.1 (3303), superfeeder[superfeeder]@[172.21.1.184]
SELECT * FROM `users` WHERE (one_week_anniversary_sent = N AND activated_at < 'S')
Count: 21 Time=0.00s (0s) Lock=0.00s (0s) Rows=0.0 (0), 0users@0hosts
administrator command: Ping
Count: 1 Time=0.00s (0s) Lock=0.00s (0s) Rows=0.0 (0), debian-sys-maint[debian-sys-maint]@localhost
select count(*) into @discard from `information_schema`.`COLUMNS`
Count: 8 Time=0.00s (0s) Lock=0.00s (0s) Rows=30.0 (240), superfeeder[superfeeder]@[172.21.1.184]
SELECT DISTINCT `feeds`.* FROM `feeds` INNER JOIN `subscriptions` ON `feeds`.id = `subscriptions`.feed_id WHERE ((`subscriptions`.user_id = N)) AND ((`subscriptions`.user_id = N)) LIMIT N, N
Count: 31 Time=0.00s (0s) Lock=0.00s (0s) Rows=1.0 (31), superfeeder[superfeeder]@2hosts
SELECT count(*) AS count_all FROM `feeds`
Count: 1 Time=0.00s (0s) Lock=0.00s (0s) Rows=0.0 (0), debian-sys-maint[debian-sys-maint]@localhost
select count(*) into @discard from `information_schema`.`TRIGGERS`
Count: 1 Time=0.00s (0s) Lock=0.00s (0s) Rows=0.0 (0), debian-sys-maint[debian-sys-maint]@localhost
select count(*) into @discard from `information_schema`.`VIEWS`
Count: 52 Time=0.00s (0s) Lock=0.00s (0s) Rows=0.7 (34), superfeeder[superfeeder]@[172.21.1.184]
SELECT * FROM `users` WHERE (`users`.`remember_token` = 'S') LIMIT N
Count: 120 Time=0.00s (0s) Lock=0.00s (0s) Rows=1.0 (120), superfeeder[superfeeder]@2hosts
SELECT * FROM `feeds` ORDER BY feeds.id DESC LIMIT N
Count: 19 Time=0.00s (0s) Lock=0.00s (0s) Rows=15.7 (299), superfeeder[superfeeder]@2hosts
SELECT count(*) AS count_all, last_http_code AS last_http_code FROM `feeds` GROUP BY last_http_code
Count: 1 Time=0.00s (0s) Lock=0.00s (0s) Rows=0.0 (0), debian-sys-maint[debian-sys-maint]@localhost
select count(*) into @discard from `information_schema`.`ROUTINES`
Count: 1 Time=0.00s (0s) Lock=0.00s (0s) Rows=1.0 (1), debian-sys-maint[debian-sys-maint]@localhost
SELECT count(*) FROM mysql.user WHERE user='S' and password='S'
提要的表定义：
+---------------------+--------------+------+-----+---------------------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------------------+--------------+------+-----+---------------------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| url | varchar(255) | YES | UNI | NULL | |
| last_parse | datetime | YES | | 2009-08-10 14:51:46 | |
| etag | varchar(255) | YES | | etag | |
| modified | datetime | YES | | 2009-08-10 14:51:46 | |
| active | tinyint(1) | YES | MUL | 1 | |
| last_fetch | datetime | YES | | 2009-08-10 14:51:46 | |
| next_fetch | datetime | YES | MUL | 2009-08-10 14:51:46 | |
| fetch_session_id | varchar(255) | YES | MUL | | |
| period | int(11) | YES | | 240 | |
| hashed_content | varchar(255) | YES | | | |
| streamed | tinyint(1) | YES | | 0 | |
| sup_id | varchar(255) | YES | MUL | NULL | |
| last_sup_update_id | varchar(255) | YES | | NULL | |
| last_entry_time | datetime | YES | | 2009-08-10 14:51:46 | |
| last_ping | datetime | YES | | NULL | |
| last_http_code | int(11) | YES | | NULL | |
| last_error_message | varchar(255) | YES | | | |
| sup_url_id | int(11) | YES | MUL | NULL | |
| created_at | datetime | YES | | NULL | |
| updated_at | datetime | YES | | NULL | |
| last_maintenance_at | datetime | YES | | 2008-08-10 21:51:50 | |
| min_period | int(11) | YES | | 60 | |
| max_period | int(11) | YES | | 900 | |
+---------------------+--------------+------+-----+---------------------+----------------+
+-------+------------+--------------------------------------+--------------+------------------+-----------+-------------+----------+--------+------+------------+---------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment |
+-------+------------+--------------------------------------+--------------+------------------+-----------+-------------+----------+--------+------+------------+---------+
| feeds | 0 | PRIMARY | 1 | id | A | 166 | NULL | NULL | | BTREE | |
| feeds | 0 | index_feeds_on_url | 1 | url | A | 166 | NULL | NULL | YES | BTREE | |
| feeds | 1 | index_feeds_on_next_fetch_and_active | 1 | next_fetch | A | 1 | NULL | NULL | YES | BTREE | |
| feeds | 1 | index_feeds_on_next_fetch_and_active | 2 | active | A | 1 | NULL | NULL | YES | BTREE | |
| feeds | 1 | index_feeds_on_sup_id | 1 | sup_id | A | 1 | NULL | NULL | YES | BTREE | |
| feeds | 1 | index_feeds_on_sup_url_id | 1 | sup_url_id | A | 1 | NULL | NULL | YES | BTREE | |
| feeds | 1 | index_feeds_on_fetch_session_id | 1 | fetch_session_id | A | 1 | NULL | NULL | YES | BTREE | |
+-------+------------+--------------------------------------+--------------+------------------+-----------+-------------+----------+--------+------+------------+---------+
哪些内核参数或其他设置控制 Linux 服务器上可以打开的 TCP 套接字的最大数量？允许更多连接的权衡是什么？
我注意到在使用ab对 Apache 服务器进行负载测试时，很容易将服务器上的打开连接最大化。如果您不使用允许连接重用的 ab 的 -k 选项，并让它发送超过 10,000 个请求，那么 Apache 会处理前 11,000 个左右的请求，然后停止 60 秒。查看 netstat 输出显示 11,000 个连接处于 TIME_WAIT 状态。显然，这是正常的。出于TCP 可靠性的原因，即使在客户端完成连接后，连接仍会保持默认打开 60 秒。
看起来这将是一种对服务器进行 DoS 的简单方法，我想知道通常的调整和预防措施是什么。
这是我的测试输出：
# ab -c 5 -n 50000 http://localhost/
This is ApacheBench, Version 2.0.40-dev <$Revision: 1.146 $> apache-2.0
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Copyright 2006 The Apache Software Foundation, http://www.apache.org/
Benchmarking localhost (be patient)
Completed 5000 requests
Completed 10000 requests
apr_poll: The timeout specified has expired (70007)
Total of 11655 requests completed
这是我在测试期间运行的 netstat 命令：
# netstat --inet -p | grep "localhost:www" | sed -e 's/ \+/ /g' | cut -d' ' -f 1-4,6-7 | sort | uniq -c
11651 tcp 0 0 localhost:www TIME_WAIT -
1 tcp 0 1 localhost:44423 SYN_SENT 7831/ab
1 tcp 0 1 localhost:44424 SYN_SENT 7831/ab
1 tcp 0 1 localhost:44425 SYN_SENT 7831/ab
1 tcp 0 1 localhost:44426 SYN_SENT 7831/ab
1 tcp 0 1 localhost:44428 SYN_SENT 7831/ab
我有一个高 IO 应用程序正在运行，并且迄今为止可以很好地扩展。在过去的几个月里，我们一直在努力展望未来并预测下一个瓶颈将发生在哪里。其中之一肯定是文件系统。
我们目前正在监控
这对我来说似乎有点太稀疏了。我还应该看什么？我什至不确定操作/秒的“黄线”是什么。
