cat /etc/redhat-release
CentOS release 5.3 (Final)


Next step is to download the latest MySQL 5.1 community release matching the OS and architecture from
http://dev.mysql.com/downloads/mysql/5.1.html#downloads


wget http://dev.mysql.com/get/Downloads/MySQL-5.1/MySQL-server-community-5.1.35-0.rhel5.x86_64.rpm/from/http://mirror.csclub.uwaterloo.ca/mysql/

wget http://dev.mysql.com/get/Downloads/MySQL-5.1/MySQL-devel-community-5.1.35-0.rhel5.x86_64.rpm/from/http://mirror.csclub.uwaterloo.ca/mysql/


The download folder should look something like

ls
./ MySQL-client-community-5.1.35-0.rhel5.x86_64.rpm MySQL-server-community-5.1.35-0.rhel5.x86_64.rpm
../ MySQL-devel-community-5.1.35-0.rhel5.x86_64.rpm MySQL-shared-community-5.1.35-0.rhel5.x86_64.rpm


! FOLLOWING STEPS ARE VERY IMPORTANT

We must backup the current mysql setup as best as possible !.

cp -pvr /var/lib/mysql /var/lib/mysql.original.jun17
mysqldump --add-drop-database --all-databases > mysql.backup.jun17.sql

cp -p /etc/my.cnf /etc/my.cnf.original.jun17
cp -p /root/.my.cnf /root/.my.cnf.original.jun17
cp -p /etc/init.d/mysql /etc/init.d/mysql.original.jun17


Now we remove the current MySQL rpm’s

rpm -e MySQL-bench-5.0.81-0.glibc23
rpm -e MySQL-devel-5.0.81-0.glibc23
rpm -e MySQL-client-5.0.81-0.glibc23
rpm -e MySQL-server-5.0.81-0.glibc23
rpm -e MySQL-shared-5.0.81-0.glibc23


Install the new MySQL rpm’s

rpm -Uvh MySQL-server-community-5.1.35-0.rhel5.x86_64.rpm
rpm -Uvh MySQL-client-community-5.1.35-0.rhel5.x86_64.rpm
rpm -Uvh MySQL-shared-community-5.1.35-0.rhel5.x86_64.rpm
rpm -Uvh MySQL-devel-community-5.1.35-0.rhel5.x86_64.rpm


Copy over the original mysql init script

cp -p /etc/init.d/mysql /etc/init.d/mysql.bad
cp -p /etc/init.d/mysql.original.jun17 /etc/init.d/mysql


start mysql

/etc/init.d/mysql start


If there is a problem ,check the mysql error log for details

Run the following command to complete the mysql upgrade

mysql_upgrade


DESCRIPTION
mysql_upgrade should be executed each time you upgrade MySQL. It supersedes the older
mysql_fix_privilege_tables script, which should no longer be used.

mysql_upgrade checks all tables in all databases for incompatibilities with the current version of MySQL
Server. If a table is found to have a possible incompatibility, it is checked. If any problems are found,
the table is repaired. mysql_upgrade also upgrades the system tables so that you can take advantage of new
privileges or capabilities that might have been added.

Thats it.

Now your php mysql module is broken .So it is very important that you recompile either php alone or use easyapache3 to recompile apache and php with a forced rebuild of php !

We have to enable networking ;if it is skipped. Enable binary logging and start a binary log of all databases

Add the following to the my.cnf file and restart MySQL


server-id = 1
log-bin=mysql-bin
binlog-do-db=gnusys_kb
binlog-do-db=gnusys_wiki
binlog-do-db=powerdns


create a user on the master with replication slave privileges on all databases from the slaves IP address

GRANT REPLICATION SLAVE ON *.* TO '*****************'@'ip.ip.ip.ip' IDENTIFIED BY '********';


The next step is to have identical data on both master and slave server .This can be accomplished by preventing all writes on the master for some time and take a snapshot of the databases on the master using mysqldump and restore all of them on the slave

FLUSH TABLES WITH READ LOCK;


Keep this prompt running;inoder that the lock is active

mysqldump db1 –lock-all-tables > db1.june14.sql
mysqldump gnusys_kb –lock-all-tables > powerdns.june14.sql
………………

and on the slave server restore the databases.

The next step is to get some vital information from the master to initiate replication on the slave.On masters mysql prompt run

SHOW MASTER STATUS;
+------------------+----------+---------------------------------------------------------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+---------------------------------------------------------------+------------------+
| mysql-bin.000001 | 1547443 | gnusys_kb,gnusys_wiki,powerdns,gnusys_kb,gnusys_wiki,powerdns | |
+------------------+----------+---------------------------------------------------------------+------------------+
1 row in set (0.00 sec)


add the following to the my.cnf of the slave server

#Mysql slave settings
server-id = 2
master-host=174.136.4.248
master-user=******************
master-password=*********
master-connect-retry=60
replicate-do-db=gnusys_kb
replicate-do-db=gnusys_wiki
replicate-do-db=powerdns


Restart slave mysql

Now we remote the write lock on the master.On masters mysql prompt which we kept running

UNLOCK TABLES;


On the slaves mysql prompt run the following

SLAVE STOP;

START SLAVE;
quit;


Thats it!.

The status of master can be known from

SHOW MASTER STATUS;


and slave can be known by

SHOW SLAVE STATUS;


Since Cpanel compiles httpd from source ; it is best we compile svn also from source and install the mod_dav_svn apache2 module along with it. Please note that you must have apache2.0 inoder for this to work

Step1 - mod_dav_svn requires mod_dav to be present.So ensure that you have selected dav in your easyapache 3 configuration

This can be confirmed by

===============================

===============================

Next we have to download subversion source. I have used the latest source at the time of writing; so please use what is latest now

cd /usr/local/src

Please note that you must substitute the correct directories in configure line above suitable to your system. The system i had was using httpd-2.2.11

The make install step will add the LoadModule line in httpd.conf.For clarity purpose of cpanels ea3 system.we remove those lines from httpd.conf and add it in

WHM - Apache Setup - Include Editor - Pre-Main Include

and save the configuration

Thats it !.The next step would be to configure apache as per your requirement and according to the documentation of including custom edits in cpanels ea3 system:
http://svnbook.red-bean.com/en/1.1/ch06s04.html
http://www.cpanel.net/documentation/easyapache/customdirectives.html

AddType application/x-httpd-php4 .php4
AddHandler application/x-httpd-php4 .php4

The above two  lines looks similar except for the difference in AddType and AddHandler directive names, but we can differentiate between them by their use ie AddType is for the client and AddHandler is for server to understand.If you ask how browsers actually deal with the content type you set in your AddType directive, then the answer is :- Gecko ( Gecko is a layout engine used by Firefox ) based browsers (like Firefox) follow the standard closely so they will handle a file according to the content type in your Apache configuration. This means your image will show up as text if you wrongly assigned the text/plain content type. Internet Explorer is more flexible and tries to guess the mime type for misconfigured web servers showing a wrongly defined images as, well, an image

Security Aspects :-

Some content types, such as executable programs, are inherently unsafe. For this reason these MIME types are usually restricted in terms of what actions a web browser will take when given content of that type. An executable program should not be executed on the user’s computer and at most should cause a dialog to appear asking the user if they wish to download the file.

MIME type guessing has led to security exploits in Internet Explorer which were based upon a malicious author incorrectly reporting a MIME type of a dangerous file as a safe type. This bypassed the normal download dialog resulting in Internet Explorer guessing that the content was an executable program and then running it on the user’s computer.

Before you start reading anything about MPM, multi threading etc first thing you need to understand is the difference between a  Process and a Thread and then everything would turn out to be simple. A single process can have multiple threads that share global data and address space with other threads running in the same process, and therefore can operate on the same data set easily. Processes do not share address space and a different mechanism must be used if they are to share data.

If we consider running a word processing program to be a process, then the auto-save and spell check features that occur in the background are different threads of that process which are all operating on the same data set (your document).

Process

In computing, a process is an instance of a computer program that is being sequentially executed by a computer system that has the ability to run several computer programs concurrently.

Thread

A single process may contain several executable programs (threads) that work together as a coherent whole. One thread might, for example, handle error signals, another might send a message about the error to the user, while a third thread is executing the actual task

So the main difference between prefork MPM and worker MPM is :-

• The  worker MPM uses multiple child processes with many threads each. Each thread handles one connection at a time. By using threads to serve requests, it is able to serve a large number of requests with less system resources than a process-based server. Yet it retains much of the stability of a process-based server by keeping multiple processes available, each with many threads. Worker generally is a good choice for high-traffic servers because it has a smaller memory footprint than the prefork MPM.
• The  prefork MPM uses multiple child processes with one thread each. Each process handles one connection at a time. On many systems, prefork is comparable in speed to worker, but it uses more memory. Prefork’s threadless design has advantages over worker in some situations: it can be used with non-thread-safe third-party modules, and it is easier to debug on platforms with poor thread debugging support.

CPUUNITS=”5000″
Analysis of a vps
———————–
vzcpucheck
Current CPU utilization: 227090
Power of the node: 781118

What this says is that node has 781000~ cpuunits available with the processors which it has there. What your host should do, is figure out how many VPSs your host is planning to run on the server, for example in such a case with 800000 cpuunits it would be acceptable to run certain number of VPSs with 5000, and other higher plans with 7500 or 10000 cpuunits.

This is used for tracking quota for all your files in the system. The more files you have in your system, the more quotaugidlimit is required . quotaugidlimit is used to track the numer of group and users with quotas. As you add more users and groups it gets near the limit.

This command will show you current usage of second-level quotas in a VE #101, you may run it on a hardware node:
wc -l /vz/root/101/etc/{passwd,group}
95 /vz/root/101/etc/passwd
107 /vz/root/101/etc/group
202 total

You may increase QUOTAUGIDLIMIT parameter using ‘vzctl’ utility on a node:
# vzctl set 101 –save –quotaugidlimit 210

where 101 is the VPS node id

To apply changes it is required to restart VE:
# vzctl restart 101

Stop exim
# /etc/init.d/exim stop

Edit your exim configuration file.
# vi /etc/exim.con or take Exim configuration Editor at WHM
go to “remote_smtp” section under “TRANSPORTS CONFIGURATION”.

By default it would look like below:
Quote:
remote_smtp:
driver = smtp
interface = ${if exists {/etc/mailips}{${lookup{$sender_address_domain}lsearch{/etc/mailips}{$value}{}}}{}}
helo_data = ${if exists {/etc/mailhelo}{${lookup{$sender_address_domain}lsearch{/etc/mailhelo}{$value}{$primary_hostname}}}{$primary_ho stname}}

Remove or comment line containing “interface” and “helo_data” and add new “interface” to match with that of your new IP address. It should look like as follows:
Quote:
remote_smtp:
driver = smtp
interface = 79.99.65.167 # Your new Mail server IP address.

Now save your changes and exit out from your exim configuration file.

Note : Dont forget to set read only attributes on exim configuration file, so that it wont get reset to default automatically ( It  might get removed in new Cpanel/WHM versions but if you have used the “Exim configuration editor” option under WHM this change will remain intact over further updates).

And if you are setting an attribute you can do it using following command:
# chattr +aui /etc/exim.conf

Start exim service on your server.
# service exim restart or /etc/init.d/exim restart

Setting a reverse DNS for this new IP address to point a valid FQDN would be a good idea and we recommend this. Now
try sending a test email and you will find that, it was sent using this new IP address configured under your exim configuration.

If you get this error, you’ve most likely done a file-based MySQL backup restore, and the InnoDB files are not present. The horde_sessionhandler table is an InnoDB table but not a MyISAM.

To fix this first you will need to stop mysql
# /etc/init.d/mysqld stop

Then remove the innoDB table
# rm /var/lib/mysql/horde/horde_sessionhandler.frm

Then start MySQL

# /etc/init.d/mysqld start

Now re-create the table:
# mysql -u admin -p`cat /etc/psa/.psa.shadow`
mysql>CREATE TABLE horde_sessionhandler (session_id VARCHAR(32) NOT NULL, session_lastmodified INT NOT NULL, session_data LONGBLOB, PRIMARY KEY (session_id)) ENGINE = InnoDB;
GRANT SELECT, INSERT, UPDATE, DELETE ON horde_sessionhandler TO horde@localhost;