jpuyy的网志

Category: Life

  • 命令行访问memcached

    有很多的web端和GUI可以访问到Memcached服务，比如phpMemCacheAdmin，但是有些时候需要在命令行进行Memcached的访问。 在本教程中使用Telnet来攻取Memcached信息，以及如何读取与删除数据。 连接

    telnet localhost 11211

    获取服务信息，如pid, uptime, version, 条目数, 连接数

    stats

    获取slab信息，那么什么是slab Memory is allocated in chunks internally and constantly reused. Since memory is broken into different size slabs, you do waste memory if your items do not fit perfectly into the slab the server chooses to put it in. Memcached会根据你数据的大小来存放不同的slab，可以理解为片或分区，这样不会浪费内存。

    stats slabs

    获取条目信息

    stats items

    访问和删除数据

    知道slab的概念和信息之后，可以使用如下命令访问slab

    stats cachedump [slab ID] [number of items, 0 for all items]

    如在ID=36的slab中有3个条目

    stats cachedump 36 0
ITEM model1 [223301 b; 1383751902 s]
ITEM modelNodeid1 [223301 b; 1383751902 s]
ITEM id1 [223300 b; 1383751902 s]
END

    获取id1

    get id1

    删除id1

    delete id1

    退出

    quit 或 ctrl + ]

    Command Description Example

    get Reads a value get mykey
    set Set a key unconditionally set mykey 0 60 5
    add Add a new key add newkey 0 60 5
    replace Overwrite existing key replace key 0 60 5
    append Append data to existing key append key 0 60 15
    prepend Prepend data to existing key prepend key 0 60 15
    incr Increments numerical key value by given number incr mykey 2
    decr Decrements numerical key value by given number decr mykey 5
    delete Deletes an existing key delete mykey
    flush_all Invalidate specific items immediately flush_all
    Invalidate all items in n seconds flush_all 900
    stats Prints general statistics stats
    Prints memory statistics stats slabs
    Prints memory statistics stats malloc
    Print higher level allocation statistics stats items
    stats detail
    stats sizes
    Resets statistics stats reset
    version Prints server version. version
    verbosity Increases log level verbosity
    quit Terminate telnet session quit

    参考： http://www.alphadevx.com/a/90-Accessing-Memcached-from-the-command-line

  • column命令

    想要使文本以整齐的tab表示，可以使用column -t命令

    例子：

    [mysqld_multi]
mysqld = /usr/local/mysql/bin/mysqld_safe
mysqladmin = /usr/local/mysql/bin/mysqladmin
user = root
log = /var/log/mysqld_multi.log

[mysqld3306]
port = 3306
socket = /tmp/mysql3306.sock
pid-file = /var/run/mysql/mysql3306.pid
datadir = /data/innodb
user = mysql

    写入到my.test.cnf中

    运行

    column -t my.test.cnf

    变成了

    [mysqld_multi]
mysqld          =  /usr/local/mysql/bin/mysqld_safe
mysqladmin      =  /usr/local/mysql/bin/mysqladmin
user            =  root
log             =  /var/log/mysqld_multi.log
[mysqld3306]
port            =  3306
socket          =  /tmp/mysql3306.sock
pid-file        =  /var/run/mysql/mysql3306.pid
datadir         =  /data/innodb
user            =  mysql

  • MySQL/MariaDB单机多实例配置

    在同一台服务器上可以配置mysql多实例，提高服务器的使用率

    这里mysql的目录为/usr/local/mysql/，开两个实例，存放目录分别为

    /data/db1
/data/db2

    分别监听3306, 3307

    接下来写好/etc/my.cnf内容，主要注意sock, pid, log

    [mysqld_multi]
mysqld = /usr/local/mysql/bin/mysqld_safe
mysqladmin = /usr/local/mysql/bin/mysqladmin
user = root
log = /var/log/mysqld_multi.log

[mysqld3306]
port = 3306
socket = /tmp/mysql3306.sock
pid-file = /var/run/mysql/mysql3306.pid
datadir = /data/innodb
user=mysql
log-error=/var/log/mysql_error3306.log
default-storage-engine = INNODB
innodb_read_io_threads = 16
innodb_write_io_threads = 4
innodb_io_capacity = 4000
back_log = 50
max_connections = 2000
max_prepared_stmt_count=500000
max_connect_errors = 10
table_open_cache = 2048
max_allowed_packet = 16M
binlog_cache_size = 16M
max_heap_table_size = 64M
sort_buffer_size = 4M
join_buffer_size = 4M
thread_cache_size = 1000
query_cache_size = 0
query_cache_type = 0
thread_stack = 192K
tmp_table_size = 64M
server-id = 10
key_buffer_size = 8M
read_buffer_size = 1M
read_rnd_buffer_size = 4M
bulk_insert_buffer_size = 8M
myisam_sort_buffer_size = 8M
myisam_max_sort_file_size = 10G
myisam_repair_threads = 1
myisam_recover

[mysqld3307]
port = 3307
socket = /tmp/mysql3307.sock
pid-file = /var/run/mysql/mysql-3307.pid
datadir = /data/tokudb
user=mysql
log-error=/var/log/mysql_error3307.log
back_log = 50
max_connections = 2000
max_prepared_stmt_count=500000
max_connect_errors = 10
table_open_cache = 2048
max_allowed_packet = 16M
binlog_cache_size = 16M
max_heap_table_size = 64M
sort_buffer_size = 4M
join_buffer_size = 4M
thread_cache_size = 1000
query_cache_size = 0
query_cache_type = 0
ft_min_word_len = 4
thread_stack = 192K
tmp_table_size = 64M
server-id = 10
key_buffer_size = 8M
read_buffer_size = 1M
read_rnd_buffer_size = 4M
bulk_insert_buffer_size = 8M
myisam_sort_buffer_size = 8M
myisam_max_sort_file_size = 10G
myisam_repair_threads = 1
myisam_recover

    安装数据文件

    cd /usr/local/mysql/
./scripts/mysql_install_db --datadir=/data/db1/ --user=mysql
./scripts/mysql_install_db --datadir=/data/db2/ --user=mysql

    创建启动脚本

    cp /usr/local/mysql/support-files/mysqld_multi.server /etc/init.d/mysqld_multi
chmod u+x /etc/init.d/mysqld_multi

    为方便使用，将/usr/local/mysql/bin加入到PATH中

    export PATH=/usr/local/mysql/bin:$PATH

    启动实例

    /etc/init.d/mysqld_multi start 3306
/etc/init.d/mysqld_multi start 3307

    查看启动的情况

    netstat -tnlp

  • AWStats on Debian

    https://wiki.debian.org/Manual-Howto#AWStats_on_Debian

  • 能让我心静下来的一些东西

    道德经

    红楼梦

    经典美文

    一些歌曲：亲密爱人

    总节一下就是 文字与音乐。

  • ssh-agent使用笔记

    ssh-agent是管理多个ssh key的代理，受管理的私钥通过ssh-add来添加

    好处1：不用重复输入密码。
    用 ssh-add 添加私钥时，如果私钥有密码的话，照例会被要求输入一次密码，在这之后ssh-agent可直接使用该私钥，无需再次密码认证。

    好处2：不用到处部署私钥
    假设私钥分别可以登录同一内网的主机 A 和主机 B，出于一些原因，不能直接登录 B。可以通过在 A 上部署私钥或者设置 Forwarding 登录 B，也可以转发认证代理连接在 A 上面使用ssh-agent私钥登录 B；可以在A上直接sftp传文件到B上。

    如这边有一台机器是local，能通过公钥直接登陆server1和server2。server1和server2之间无公钥登陆。

    现在要在server1上直接登陆server2，在local上执行

    ssh-agent
ssh-add

    接下来登陆server1，注意-A

    ssh -A server1

    可以发现server1上多了/tmp/ssh-xxxxxxxxx/agent.xxxxx的socket，之后神奇的事发生了，在server1上可直接进server2，只需执行如下命令，如果加了-A则可以继续ssh forwarding，以至无限的机器forwarding。

    ssh (-A) server2

    同样的原理可以试一下sftp, scp等基于ssh的命令。

    如运行ssh-add，遇到“Could not open a connection to your authentication agent.”。

    解决：需要ssh-agent启动bash，或者说把bash挂到ssh-agent下面。

    eval "$(ssh-agent -s)"
ssh-add

    list the agent managed identities

    ssh-add -l

    delete all agent managed identities

    ssh-add -D

    参考：
    http://www.cnblogs.com/cheche/archive/2011/01/07/1918825.html
    http://blog.pkufranky.com/2012/08/ssh-agent-forwarding-guide/
    http://blog.jobbole.com/33790/