Tôi đang chạy một máy chủ cơ sở dữ liệu rackspace RAM 1gb. Vì một số lý do trong khoảng 2 ngày, việc sử dụng bộ nhớ chuyển từ sử dụng rất ít trao đổi, sang sử dụng 100mb. Nếu tôi không khởi động lại sql, nó sẽ tiếp tục sử dụng nhiều trao đổi hơn. (Tệp my.cnf của tôi được hiển thị bên dưới và sử dụng bộ nhớ được hiển thị bên dưới)
Một số nền tảng: Tôi có khoảng 50 cơ sở dữ liệu hoạt động có cùng lược đồ sử dụng INNODB cho các bảng. Tôi có một vài cơ sở dữ liệu với ít lưu lượng sử dụng MyISAM.
Trên các bảng INNODB tôi KHÔNG sử dụng các kết nối liên tục. Tôi cũng có một chức năng báo cáo tạo ra một bảng tạm thời. (Điều này có thể tốn nhiều tài nguyên, nhưng KHÔNG xảy ra thường xuyên)
Tôi đang sử dụng CENTOS 6.3 và mysql 5.5.28-log
Mặc dù tôi đang sử dụng trao đổi, hiệu suất vẫn khá tốt. Tôi chỉ sợ rằng nếu tôi không khởi động lại cứ sau vài ngày tôi sẽ gặp vấn đề.
Đây là nhật ký miễn phí của tôi trong khoảng 2 ngày: (Bản ghi đầu tiên là ngay sau khi khởi động lại mysql)
12/26 2:08 PM EST
total used free shared buffers cached
Mem: 992 697 295 0 74 362
-/+ buffers/cache: 260 732
Swap: 976 15 961
12/26 4:10 PM EST
[root@php-pos-db ~]# free -m
total used free shared buffers cached
Mem: 992 791 201 0 97 405
-/+ buffers/cache: 287 705
Swap: 976 14 961
12/27 2:52 PM EST
[root@php-pos-db ~]# free -m
total used free shared buffers cached
Mem: 992 947 45 0 55 169
-/+ buffers/cache: 722 270
Swap: 976 34 942
12/28 1:41 PM EST
total used free shared buffers cached
Mem: 992 963 29 0 45 119
-/+ buffers/cache: 797 195
Swap: 976 48 927
12/28 7:24 PM EST
[root@php-pos-db ~]# free -m
total used free shared buffers cached
Mem: 992 957 35 0 41 141
-/+ buffers/cache: 774 218
Swap: 976 90 886
12/28 8:33 PM EST
[root@php-pos-db ~]# free -m
total used free shared buffers cached
Mem: 992 948 44 0 48 130
-/+ buffers/cache: 768 224
Swap: 976 96 880my.cnf
# The MySQL database server configuration file.
#
# You can copy this to one of:
# - "/etc/mysql/my.cnf" to set global options,
# - "~/.my.cnf" to set user-specific options.
#
# One can use all long options that the program supports.
# Run program with --help to get a list of available options and with
# --print-defaults to see which it would actually understand and use.
#
# For explanations see
# http://dev.mysql.com/doc/refman/5.1/en/server-system-variables.html
#
# Take care to only add/remove/change a setting if you are comfortable
# doing so! For Rackspace customers, if you have any questions or
# concerns, please contact the MySQL Database Services Team. Be aware
# that some work performed by this team can involve additional billable
# fees.
#
# This file generated for host php-pos-db please modify
# variables if the server is resized from 1016636kB
[mysqld]
### General
user = mysql
port = 3306
datadir = /var/lib/mysql
tmpdir = /tmp
socket = /var/lib/mysql/mysql.sock
skip-external-locking = 1
log_error = /var/log/mysqld.log
## This prevents using host-based authentication. That means users must be
## created using an ip-address (ie 'myuser'@'192.168.100.1') or must make
## use of the % wildcard (ie 'myuser'@'%'). The benefit to not using
## host-based authentication is that DNS will not impact MySQL performance.
#skip-name-resolve
## If open-files-limit is set very low, MySQL may increase on its own. Either
## way, increase this if MySQL gives 'too many open files' errors. Setting
## this above 65535 could be unwise (MySQL may crash).
open-files-limit = 20000
### Cache
thread-cache-size = 16
table-open-cache = 4096
table-definition-cache = 512
## Generally, it is unwise to set the query cache to be larger than 64-128M
## as the costs associated with maintaining the cache outweigh the performance
## gains. A far superior solution would be to implement memcached, though this
## required modifying the application, among other things.
query-cache-type = 1
query-cache-size = 32M
query-cache-limit = 1M
### Per-thread Buffers
sort-buffer-size = 1M
read-buffer-size = 1M
read-rnd-buffer-size = 2M
join-buffer-size = 1M
### Temp Tables
tmp-table-size = 64M
max-heap-table-size = 64M
### Networking
back-log = 100
max-connections = 50
max-connect-errors = 10000
max-allowed-packet = 16M
interactive-timeout = 600
wait-timeout = 180
net_read_timeout = 30
net_write_timeout = 30
# This value is the size of the listen queue for incoming TCP/IP connections.
back_log = 128
#### Storage Engines
## Set this to force MySQL to use a particular engine / table-type
## for new tables. This setting can still be overridden by specifying
## the engine explicitly in the CREATE TABLE statement.
default-storage-engine = InnoDB
## Makes sure MySQL does not start if InnoDB fails to start. This helps
## prevent ugly silent failures.
innodb = FORCE
### MyISAM
## Not sure what to set this to?
## Try running a 'du -sch /var/lib/mysql/*/*.MYI'
## This will give you a good estimate on the size of all the MyISAM indexes.
## (The buffer may not need to set that high, however)
key-buffer-size = 2M
## This setting controls the size of the buffer that is allocated when
## sorting MyISAM indexes during a REPAIR TABLE or when creating indexes
## with CREATE INDEX or ALTER TABLE.
myisam-sort-buffer-size = 2M
### InnoDB
## Note: While most settings in MySQL can be set at run-time, many InnoDB
## variables cannot be set at runtime as require restarting MySQL
###
## These settings control how much RAM InnoDB will use. Generally, when using
## mostly InnoDB tables, the innodb-buffer-pool-size should be as large as
## is possible without swapping or starving other processes of RAM. The other
## two settings usually do not need to be changed, but can help for very large
## datasets.
innodb-buffer-pool-size = 285M
innodb-log-buffer-size = 8M
## Be careful when changing these as they require re-generating the
## ib-logfile* files, which must be done carefully. Do not change this unless
## you are familiar with the procedure.
innodb-log-file-size = 128M
innodb-log-files-in-group = 2
## This will cause each table to create its own .ibd file
innodb-file-per-table = 1
## Setting this to 2 will decrease disk I/O but can cause up to a second of
## queries to be lost during a hard outage (i.e. power failures)
# innodb-flush-log-at-trx-commit = 2
### Replication
## Set this to the Server's instance ID in replication environments
server-id = 1
#log-bin = /var/lib/mysql/bin-log
#relay-log = /var/lib/mysql/relay-log
#relay-log-space-limit = 4G
#expire-logs-days = 5
## This should be enabled on conventional MySQL slaves
#read-only = 1
## This will cause replicated statements on a slave to be written to the slave's binlog
## Enable this on the middle slave of M->S->S configs
#log-slave-updates = 1
#binlog-format = STATEMENT
### Logging
## This option determines the destination for general query log and slow query log output.
## The option value can be given as one or more of the words TABLE, FILE, or NONE.
## NOTE: Table logging takes away 50% of performance and thus is not recommended
## http://bugs.mysql.com/bug.php?id=30414
## In addition, you cannot backup the contents of these tables properly
## (mysqldump skips these tables by default since they cannot be locked)
#log-output = FILE
slow-query-log = 1
slow-query-log-file = /var/lib/mysql/slow-log
long-query-time = 2
log-queries-not-using-indexes = 1
[mysqld-safe]
log-error = /var/log/mysqld.log
[mysqldump]
max-allowed-packet = 16M
# * IMPORTANT: Additional settings that can override those from this file!
# The files must end with '.cnf', otherwise they'll be ignored.
#
!includedir /etc/sysconfig/mysqld-config/