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A basic installation contains at least 2 database servers and 1 monitoring server. In this guide, I used 5 servers with Debian Lenny (5.0)

I used the following virtual IPs. They will be distributed across the hosts by MMM.

一、MMM简介：

MMM即Master-Master Replication Manager for MySQL（mysql主主复制管理器）关于mysql主主复制配置的监控、故障转移和管理的一套可伸缩的脚本套件（在任何时候只有一个节点可以被写入），这个套件也能对居于标准的主从配置的任意数量的从服务器进行读负载均衡，所以你可以用它来在一组居于复制的服务器启动虚拟ip，除此之外，它还有实现数据备份、节点之间重新同步功能的脚本。

MySQL本身没有提供replication failover的解决方案，通过MMM方案能实现服务器的故障转移，从而实现mysql的高可用。

MMM项目来自 Google：http://code.google.com/p/mysql-master-master

官方网站为：http://mysql-mmm.org

Mmm主要功能由下面三个脚本提供

lmmm_mond负责所有的监控工作的监控守护进程，决定节点的移除等等

lmmm_agentd运行在mysql服务器上的代理守护进程，通过简单远程服务集提供给监控节点

lmmm_control通过命令行管理mmm_mond进程

Overview

I can remember way back when how amazed I was to order a new desktop computer with 2MB of RAM. Even the days of ordering a server with 64MB of RAM seemed like sooooo much memory. And in case you missed it, those are values in megabytes. Naturally today’s systems are in another class altogether. And while I’d like to think the quality of memory manufacturing has also increased over the years, things can still go wrong.

Failing or faulty memory doesn’t always manifest itself with a huge announcement. In the event that Windows 7 or Windows Server 2008 detects such a problem, it will most likely prompt you to run the Windows Memory Diagnostic tool. But you can also manually run this tool anytime you’d like if you prefer to be a bit more proactive.

1、checking for SSL_set_cert_store... no
configure: error: ... Error, SSL/TLS libraries were missing or unusable

安装openssl,在编译参数中添加--with-ssl=/usr/local/ssl （ssl安装路径，根据安装的实际路径设置）

2、configure: error: Cannot use an external APR-util with the bundled APR

3、httpd configure error: APR not found

At Gigahost we are managing a lot of mailboxes for our users.

At the moment these are all located on one high speced server with the outgoing SMTP split to another server.

We allow our users to connect via both IMAP and POP3 and support STARTTLS on ports 110/143 and SSL/TLS on ports 993/995.

Since we are constantly adding new users and these in turn add new mailboxes we are running out of options as to upgrade the current server. Hosting mailboxes via Courier, Dovecot or similar is very IO intensive and therefore in the long run disk IO becomes a problem.

The solution to this is ofcourse to scale the setup to more servers. Some hosting providers do this by simply adding users to a new mail server eg. mail2.example.com, mail3.example.com and so on.

What we would like to do is use a reverse proxy so that the user always connects to mail.gigahost.dk and the proxy ensures that the user is send to the correct server.

1、Using a php script on apache server as the auth backend

Start with the configuration from NginxImapProxyExample. For detail information about different configuration parameters, see the NginxMailCoreModule page.

1. Your Proxy server for pop/imap is running on 192.168.1.1
2. You have 2 backend pop/imap servers: 192.168.1.22 and 192.168.1.33
3. You have a webserver that you will use for the authentication and redirection logic 192.168.1.44.
4. The authentication script is /mail/auth.php

本专题主题收集PHP编译过程中的错误及其解决方案。
1、编译php出错
/php-5.3.2/ext/fileinfo/libmagic/apprentice.c:147:internal compiler error:Segmentation fault
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://bugzilla.redhat.com/bugzilla> for instructions.
The bug is not reproducible,so it is likely a hardware or OS problem.
make:*** [ext/fileinfo/libmagic/apprentice.lo] Error 1
解决方法：内存大于1G即可，这是php5.3.2的一个bug
--------------------------------------------------------------------
2、重新构造configure文件出错
./buildconf --force
Forcing buildconf
buildconf:checking installation…
buildconf:autoconf version 2.59 （ok）
buildconf:Your version of autoconf likely contains buggy cache code.
Running vcsclean for you.
To avoid this,install autoconf-2.13.
Can't figure out your VCS, not cleaning.
解决方法：编译安装autoconf-2.13
再将autoconf-2.13的auotconf文件至/usr/local/autoconf

How do I verify and diagnosis SSL certification installation from a Linux / UNIX shell prompt? How do I validate SSL Certificate installation and save hours of troubleshooting headaches without using a browser? How do I confirm I've the correct and working SSL certificates?

OpenSSL comes with a generic SSL/TLS client which can establish a transparent connection to a remote server speaking SSL/TLS. It’s intended for testing purposes only and provides only rudimentary interface functionality but internally uses mostly all functionality of the OpenSSL ssl library. For testing purpose I will use mail.nixcraft.net:443 SSL certificate which is issued by Go Daddy.